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1.
Neurol Res ; 44(2): 128-138, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34396932

RESUMO

OBJECTIVES: Lithium exerts a broad neuroprotective effect on the brain. This study examined whether lithium exerts therapeutic effects on stroke by restoring neural connections at the ischemic core of cortices post brain insult. METHODS: We treated rats with lithium or vehicle (saline) every 24 h for the first 72 h, starting at the beginning of reperfusion after inducing middle cerebral artery occlusion (MCAO) in rats. Somatosensory evoked potential (SSEP) recording and behavioral testing were employed to evaluate the beneficial effects of lithium treatment. To examine the effects of lithium-induced neuroplasticity, we evaluated the dendritic morphology in cortex pyramidal cells and the primary neuronal cell culture that underwent brain insults and oxygen and glucose deprivation (OGD), respectively. RESULTS: The results demonstrated that rats subjected to MCAO had prolonged N1 latency and a decreased N1/P1 amplitude at the ipsilateral cortex. Four doses of lithium reduced the brain infarction volume and enhanced the SSEP amplitude. The results of neurobehavioral tests demonstrated that lithium treatment improved sensory function, as demonstrated by improved 28-point clinical scale scores. In vitro study results showed that lithium treatment increased the dendritic lengths and branches of cultured neurons and reversed the suppressive effects of OGD. The in vivo study results indicated that lithium treatment increased cortical spine density in various layers and resulted in the development of the dendritic structure in the contralateral hemisphere. CONCLUSION: Our study confirmed that neuroplasticity in cortical neurons is crucial for lithium-induced brain function 50 recovery after brain ischemia.


Assuntos
Córtex Cerebral/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Infarto da Artéria Cerebral Média/complicações , AVC Isquêmico/complicações , Compostos de Lítio/farmacologia , Plasticidade Neuronal/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Células Piramidais/efeitos dos fármacos , Traumatismo por Reperfusão/etiologia , Traumatismo por Reperfusão/prevenção & controle , Animais , Células Cultivadas , Modelos Animais de Doenças , Compostos de Lítio/administração & dosagem , Fármacos Neuroprotetores/administração & dosagem , Ratos
2.
BMC Anesthesiol ; 21(1): 240, 2021 10 07.
Artigo em Inglês | MEDLINE | ID: mdl-34620093

RESUMO

BACKGROUND: Better protection can be provided during neurosurgery due to the establishment of somatosensory-evoked potential (SEP) and motor-evoked potential (MEP) monitoring technologies. However, some studies have showed that inhaled halogenated anesthetics have a significant impact on neurophysiological monitoring. METHODS: A total of 40 consecutive patients undergoing neurosurgery were randomly assigned to two groups receiving inhaled anesthetics, either desflurane or sevoflurane. Multiples levels (concentrations of 0.3, 0.6 and 0.9) of anesthetics were administered at minimum alveolar concentration (MAC), and then the latencies and amplitudes of SEPs and MEPs were recorded. RESULTS: SEP and MEP signals were well preserved in patients who underwent neurosurgery under general anesthesia supplemented with desflurane or sevoflurane at concentrations of 0.3, 0.6 and 0.9 MAC. In each desflurane or sevoflurane group, the amplitudes of SEPs and MEPs decreased and the latencies of SEPs were prolonged significantly as the MAC increased (P < 0.05). The SEP latencies of both the upper and lower limbs in the desflurane group were significantly longer, and the SEP amplitudes were significantly lower than those in the sevoflurane group (P < 0.05). The MEP amplitudes in the desflurane group were significantly lower than those in the sevoflurane group (P < 0.05), only the amplitudes of the upper limbs at 0.3 MAC did not vary significantly. CONCLUSIONS: SEPs and MEPs were inhibited in a dose-dependent manner by both desflurane and sevoflurane. At the same MAC concentration, desflurane appeared to have a stronger inhibitory effect than sevoflurane. All patients studied had normal neurological examination findings, hence, these results may not be applicable to patients with preexisting deficits. TRIAL REGISTRATION: The study registered on the Chinese Clinical Trial Registry ( www.chictr.org.cn ), Clinical Trials identifier ChiCTR2100045504 (18/04/2021).


Assuntos
Desflurano/farmacologia , Potencial Evocado Motor/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Monitorização Intraoperatória/métodos , Procedimentos Neurocirúrgicos , Sevoflurano/farmacologia , Adulto , Anestésicos Inalatórios/farmacologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
3.
Sci Rep ; 11(1): 20838, 2021 10 21.
Artigo em Inglês | MEDLINE | ID: mdl-34675309

RESUMO

The N13 component of somatosensory evoked potential (N13 SEP) represents the segmental response of dorsal horn neurons. In this neurophysiological study, we aimed to verify whether N13 SEP might reflect excitability changes of dorsal horn neurons during central sensitization. In 22 healthy participants, we investigated how central sensitization induced by application of topical capsaicin to the ulnar nerve territory of the hand dorsum modulated N13 SEP elicited by ulnar nerve stimulation. Using a double-blind placebo-controlled crossover design, we also tested whether pregabalin, an analgesic drug with proven efficacy on the dorsal horn, influenced capsaicin-induced N13 SEP modulation. Topical application of capsaicin produced an area of secondary mechanical hyperalgesia, a sign of central sensitization, and increased the N13 SEP amplitude but not the peripheral N9 nor the cortical N20-P25 amplitude. This increase in N13 SEP amplitude paralleled the mechanical hyperalgesia and persisted for 120 min. Pregabalin prevented the N13 SEP modulation associated with capsaicin-induced central sensitization, whereas capsaicin application still increased N13 SEP amplitude in the placebo treatment session. Our neurophysiological study showed that capsaicin application specifically modulates N13 SEP and that this modulation is prevented by pregabalin, thus suggesting that N13 SEP may reflect changes in dorsal horn excitability and represent a useful biomarker of central sensitization in human studies.


Assuntos
Sensibilização do Sistema Nervoso Central , Potenciais Somatossensoriais Evocados , Adulto , Capsaicina/efeitos adversos , Sensibilização do Sistema Nervoso Central/efeitos dos fármacos , Método Duplo-Cego , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Feminino , Humanos , Hiperalgesia/induzido quimicamente , Hiperalgesia/fisiopatologia , Masculino , Fármacos do Sistema Sensorial/efeitos adversos , Adulto Jovem
5.
Medicine (Baltimore) ; 100(25): e26356, 2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34160405

RESUMO

ABSTRACT: In dystonic and spastic movement disorders, abnormalities of motor control and somatosensory processing as well as cortical modulations associated with clinical improvement after botulinum toxin A (BoNT-A) treatment have been reported, but electrophysiological evidence remains controversial. In the present observational study, we aimed to uncover central correlates of post-stroke spasticity (PSS) and BoNT-A-related changes in the sensorimotor cortex by investigating the cortical components of somatosensory evoked potentials (SEPs). Thirty-one chronic stroke patients with PSS of the upper limb were treated with BoNT-A application into the affected muscles and physiotherapy. Clinical and electrophysiological evaluations were performed just before BoNT-A application (W0), then 4 weeks (W4) and 11 weeks (W11) later. PSS was evaluated with the modified Ashworth scale (MAS). Median nerve SEPs were examined in both upper limbs with subsequent statistical analysis of the peak-to-peak amplitudes of precentral P22/N30 and postcentral N20/P23 components. At baseline (W0), postcentral SEPs were significantly lower over the affected cortex. At follow up, cortical SEPs did not show any significant changes attributable to BoNT-A and/or physiotherapy, despite clear clinical improvement. Our results imply that conventional SEPs are of limited value in evaluating cortical changes after BoNT-A treatment and further studies are needed to elucidate its central actions.


Assuntos
Toxinas Botulínicas Tipo A/administração & dosagem , Espasticidade Muscular/tratamento farmacológico , Fármacos Neuromusculares/administração & dosagem , Reabilitação do Acidente Vascular Cerebral/métodos , Acidente Vascular Cerebral/complicações , Adulto , Idoso , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Terapia por Exercício/métodos , Feminino , Seguimentos , Humanos , Masculino , Nervo Mediano/efeitos dos fármacos , Nervo Mediano/fisiopatologia , Pessoa de Meia-Idade , Espasticidade Muscular/diagnóstico , Espasticidade Muscular/etiologia , Espasticidade Muscular/fisiopatologia , Córtex Somatossensorial/efeitos dos fármacos , Córtex Somatossensorial/fisiopatologia , Acidente Vascular Cerebral/fisiopatologia , Resultado do Tratamento , Extremidade Superior/inervação , Adulto Jovem
6.
Best Pract Res Clin Anaesthesiol ; 35(2): 221-229, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34030806

RESUMO

Dexmedetomidine can be used for sedation and analgesia and has been approved for this use by the European Medicines Agency since 2017. It causes an arousable state of sedation, which is beneficial during neurosurgical procedures that require the patient to cooperate with neurological tests (i.e. tumor surgery or implantation of deep brain stimulators). During procedures where monitoring of somatosensory evoked potentials and/or motor evoked potentials is required, dexmedetomidine can be used as an adjunct to general anesthesia with GABAergic drugs to decrease the dose of the latter when these drugs impair the monitoring signals. The use of dexmedetomidine has also been associated with neuroprotective effects and a decreased incidence of delirium, but studies confirming these effects in the peri-operative (neuro-)surgical setting are lacking. Although dexmedetomidine does not cause respiratory depression, its hemodynamic effects are complex and careful patient selection, choice of dose, and monitoring must be performed.


Assuntos
Dexmedetomidina/administração & dosagem , Potencial Evocado Motor/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Hipnóticos e Sedativos/administração & dosagem , Procedimentos Neurocirúrgicos/métodos , Dexmedetomidina/efeitos adversos , Potencial Evocado Motor/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Humanos , Insuficiência Respiratória/induzido quimicamente , Insuficiência Respiratória/fisiopatologia , Insuficiência Respiratória/prevenção & controle
7.
PLoS One ; 16(3): e0249167, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33788881

RESUMO

Watching another person's hand movement modulates somatosensory evoked magnetic fields (SEFs). Assuming that the mirror neuron system may have a role in this phenomenon, oxytocin should enhance these effects. This single-blinded, placebo-controlled, crossover study therefore used magnetoencephalography (MEG) to investigate SEFs following electrical stimulation of the right median nerve in 20 healthy male participants during hand movement observation, which were initially presented as static images followed by moving images. The participants were randomly assigned to receive either oxytocin or saline during the first trial, with the treatment being reversed during a second trial. Log-transformed ratios of the N20 and N30 amplitudes were calculated and compared between moving and static images observations. Phase locking (calculated using intertrial phase coherence) of brain oscillations was also analyzed to evaluate alpha, beta and gamma rhythm changes after oxytocin administration. Log N30 ratios showed no significant changes after placebo administration but showed a decreasing tendency (albeit not significant) after placebo administration, which may suggest mirror neuron system involvement. In contrast, log N20 ratios were increased after placebo administration, but showed no significant change after oxytocin administration. Interestingly, the gamma band activity around N20 increased after placebo administration, suggesting that oxytocin exerted an analgesic effect on median nerve stimulation, and inhibited the gamma band increase. Oxytocin might therefore modulate not only the mirror neuron system, but also the sensory processing associated with median nerve stimulation.


Assuntos
Potenciais Somatossensoriais Evocados/fisiologia , Mãos/fisiologia , Magnetoencefalografia , Ocitocina/administração & dosagem , Adulto , Encéfalo/fisiologia , Estudos Cross-Over , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade , Ocitocina/farmacologia , Efeito Placebo , Método Simples-Cego , Adulto Jovem
8.
Exp Neurol ; 341: 113687, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-33713656

RESUMO

BACKGROUND: In the adult brain, increases in neural activity lead to increases in local blood flow. However, in the preterm neonate, studies of cerebral functional haemodynamics have yielded inconsistent results, including negative responses suggesting decreased perfusion and localised tissue hypoxia, probably due to immature neurovascular coupling. Furthermore, the impact of vasoactive medications, such as dopamine and dobutamine used as inotropic therapies in preterm neonates, on cerebrovascular responses to somatosensory input is unknown. We aimed to characterise the cerebral haemodynamic functional response after somatosensory stimulation in the preterm newborn brain, with and without dopamine or dobutamine treatment. METHODS: We studied the cerebral haemodynamic functional response in 13 anaesthetised preterm lambs, using near infrared spectroscopy to measure changes in cerebral oxy- and deoxyhaemoglobin (ΔoxyHb, ΔdeoxyHb) following left median nerve stimulation using stimulus trains of 1.8, 4.8 and 7.8 s. The 4.8 and 7.8 s stimulations were repeated during dopamine or dobutamine infusion. RESULTS: Stimulation always produced a somatosensory evoked response. Majority of preterm lambs demonstrated positive functional responses (i.e. increased ΔoxyHb) in the contralateral cortex following stimulus trains of all durations. Dopamine increased baseline oxyHb and total Hb, whereas dobutamine increased baseline deoxyHb. Both dopamine and dobutamine reduced the evoked ΔoxyHb responses to 4.8 and 7.8 s stimulations. CONCLUSIONS: Somatosensory stimulation increases cerebral oxygenation in the preterm brain, consistent with increased cerebral blood flow due to neurovascular coupling. Notably, our results show that dopamine/dobutamine reduces oxygen delivery relative to consumption in the preterm brain during somatosensory stimulations, suggesting there may be a risk of intermittent localised tissue hypoxia which has clear implications for clinical practice and warrants further investigation.


Assuntos
Circulação Cerebrovascular/efeitos dos fármacos , Dobutamina/administração & dosagem , Dopamina/administração & dosagem , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Hemodinâmica/efeitos dos fármacos , Córtex Somatossensorial/efeitos dos fármacos , Animais , Animais Recém-Nascidos , Cardiotônicos/administração & dosagem , Circulação Cerebrovascular/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Hemodinâmica/fisiologia , Infusões Intravenosas , Masculino , Gravidez , Ovinos , Córtex Somatossensorial/fisiologia , Espectroscopia de Luz Próxima ao Infravermelho/métodos
9.
Proc Natl Acad Sci U S A ; 118(9)2021 03 02.
Artigo em Inglês | MEDLINE | ID: mdl-33619110

RESUMO

The organization of sensory maps in the cerebral cortex depends on experience, which drives homeostatic and long-term synaptic plasticity of cortico-cortical circuits. In the mouse primary somatosensory cortex (S1) afferents from the higher-order, posterior medial thalamic nucleus (POm) gate synaptic plasticity in layer (L) 2/3 pyramidal neurons via disinhibition and the production of dendritic plateau potentials. Here we address whether these thalamocortically mediated responses play a role in whisker map plasticity in S1. We find that trimming all but two whiskers causes a partial fusion of the representations of the two spared whiskers, concomitantly with an increase in the occurrence of POm-driven N-methyl-D-aspartate receptor-dependent plateau potentials. Blocking the plateau potentials restores the archetypical organization of the sensory map. Our results reveal a mechanism for experience-dependent cortical map plasticity in which higher-order thalamocortically mediated plateau potentials facilitate the fusion of normally segregated cortical representations.


Assuntos
Potenciais de Ação/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Rede Nervosa/fisiologia , Córtex Somatossensorial/fisiologia , Tálamo/fisiologia , Vibrissas/fisiologia , Potenciais de Ação/efeitos dos fármacos , Animais , Mapeamento Encefálico/métodos , Maleato de Dizocilpina/farmacologia , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Antagonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas GABAérgicos/farmacologia , Expressão Gênica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Rede Nervosa/anatomia & histologia , Plasticidade Neuronal/efeitos dos fármacos , Imagem Óptica , Técnicas de Patch-Clamp , Picrotoxina/farmacologia , Células Piramidais/citologia , Células Piramidais/efeitos dos fármacos , Células Piramidais/metabolismo , Receptores de GABA-A/genética , Receptores de GABA-A/metabolismo , Receptores de N-Metil-D-Aspartato/antagonistas & inibidores , Receptores de N-Metil-D-Aspartato/genética , Receptores de N-Metil-D-Aspartato/metabolismo , Córtex Somatossensorial/anatomia & histologia , Tálamo/anatomia & histologia , Vibrissas/lesões
10.
Anesthesiol Clin ; 39(1): 195-209, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33563382

RESUMO

It is important anesthesiologists understand the pharmacologic interactions of anesthetics and monitoring of evoked potentials or electroencephalography. Intravenous and inhaled anesthetics have varying degrees of influence on different monitoring modalities and can affect amplitude and latency of evoked potentials or voltage and frequency of electroencephalography. Sudden and abrupt changes in monitoring are concerning and should be evaluated promptly. The source of the changes is related to sudden modifications of anesthesia delivery, variations in vital parameters, or the result of surgical manipulation. Identifying sources of abnormal signals and determining the reason for the change should be addressed immediately and corrected accordingly.


Assuntos
Anestésicos , Potenciais Somatossensoriais Evocados , Anestésicos/farmacologia , Eletroencefalografia , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Humanos
11.
Sci Rep ; 11(1): 762, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33436821

RESUMO

Medical outcomes are strongly affected by placebo and nocebo effects. Prediction of who responds to such expectation effects has proven to be challenging. Most recent approaches to prediction have focused on placebo effects in the context of previous treatment experiences and expectancies, or personality traits. However, a recent model has suggested that basic somatosensory characteristics play an important role in expectation responses. Consequently, this study investigated not only the role of psychological variables, but also of basic somatosensory characteristics. In this study, 624 participants underwent a placebo and nocebo heat pain paradigm. Additionally, individual psychological and somatosensory characteristics were assessed. While no associations were identified for placebo responses, nocebo responses were associated with personality traits (e.g. neuroticism) and somatosensory characteristics (e.g. thermal pain threshold). Importantly, the associations between somatosensory characteristics and nocebo responses were among the strongest. This study shows that apart from personality traits, basic somatosensory characteristics play an important role in individual nocebo responses, in agreement with the novel idea that nocebo responses result from the integration of top-down expectation and bottom-up sensory information.


Assuntos
Potenciais Somatossensoriais Evocados/fisiologia , Hiperalgesia/psicologia , Efeito Nocebo , Dor/psicologia , Adolescente , Adulto , Estudos de Coortes , Condicionamento Psicológico/efeitos dos fármacos , Condicionamento Psicológico/fisiologia , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Feminino , Temperatura Alta , Humanos , Hiperalgesia/tratamento farmacológico , Hiperalgesia/fisiopatologia , Masculino , Dor/tratamento farmacológico , Dor/fisiopatologia , Efeito Placebo , Adulto Jovem
12.
Muscle Nerve ; 63(1): 99-103, 2021 01.
Artigo em Inglês | MEDLINE | ID: mdl-32710692

RESUMO

INTRODUCTION: Chronic immune polyradiculopathies (sensory, motor, and mixed) are uncommon. METHODS: In this single-center, retrospective study, the inclusion criteria for participants were progressive sensory ataxia and/or areflexic limb weakness; tibial somatosensory evoked potential (SSEP) abnormalities of the N22 and P40 potentials with normal sensory and motor nerve conduction studies or root involvement, according to magnetic resonance imaging (MRI); and albuminocytological dissociation. RESULTS: Eight patients were included in our study. Two had weakness, two had sensory ataxia, and four had both weakness and ataxia. Patients with weakness had abnormal SSEPs and patients with sensory ataxia also had absent F waves. Electromyography showed chronic denervation. MRI scans confirmed thickening and enhancement of roots. The patients responded to corticosteroid treatment. DISCUSSION: The overlapping clinicoelectrophysiological findings and similarities in radiological and therapeutic responses suggest that these entities are clinical variants of the same disease. The terms CIS(m)P, CI(s)MP, and CISMP (for chronic immune sensory motor polyradiculopathy) could be used to denote the predominant clinical involvement.


Assuntos
Corticosteroides/uso terapêutico , Condução Nervosa/efeitos dos fármacos , Polirradiculoneuropatia Desmielinizante Inflamatória Crônica/tratamento farmacológico , Polirradiculopatia/tratamento farmacológico , Adolescente , Adulto , Idoso , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Humanos , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Condução Nervosa/fisiologia , Raízes Nervosas Espinhais/efeitos dos fármacos , Raízes Nervosas Espinhais/fisiopatologia , Adulto Jovem
13.
Int J Mol Sci ; 21(22)2020 Nov 19.
Artigo em Inglês | MEDLINE | ID: mdl-33228217

RESUMO

Dry eye disease (DED) is commonly associated with ocular surface inflammation and pain. In this study, we evaluated the effectiveness of repeated instillations of transient receptor potential melastatin 8 (TRPM8) ion channel antagonist M8-B on a mouse model of severe DED induced by the excision of extra-orbital lacrimal and Harderian glands. M8-B was topically administered twice a day from day 7 until day 21 after surgery. Cold and mechanical corneal sensitivities and spontaneous ocular pain were monitored at day 21. Ongoing and cold-evoked ciliary nerve activities were next evaluated by electrophysiological multi-unit extracellular recording. Corneal inflammation and expression of genes related to neuropathic pain and inflammation were assessed in the trigeminal ganglion. We found that DED mice developed a cold allodynia consistent with higher TRPM8 mRNA expression in the trigeminal ganglion (TG). Chronic M8-B instillations markedly reversed both the corneal mechanical allodynia and spontaneous ocular pain commonly associated with persistent DED. M8-B instillations also diminished the sustained spontaneous and cold-evoked ciliary nerve activities observed in DED mice as well as inflammation in the cornea and TG. Overall, our study provides new insight into the effectiveness of TRPM8 blockade for alleviating corneal pain syndrome associated with severe DED, opening a new avenue for ocular pain management.


Assuntos
Anti-Inflamatórios/farmacologia , Síndromes do Olho Seco/tratamento farmacológico , Hiperalgesia/tratamento farmacológico , Neuralgia/tratamento farmacológico , Ácidos Nicotínicos/farmacologia , Canais de Cátion TRPM/genética , Tiofenos/farmacologia , Administração Oftálmica , Animais , Anti-Inflamatórios/uso terapêutico , Receptor 1 de Quimiocina CX3C/genética , Receptor 1 de Quimiocina CX3C/metabolismo , Quimiocina CCL2/genética , Quimiocina CCL2/metabolismo , Temperatura Baixa , Córnea/efeitos dos fármacos , Córnea/metabolismo , Córnea/fisiopatologia , Modelos Animais de Doenças , Síndromes do Olho Seco/complicações , Síndromes do Olho Seco/genética , Síndromes do Olho Seco/metabolismo , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Gânglios Parassimpáticos/efeitos dos fármacos , Gânglios Parassimpáticos/metabolismo , Gânglios Parassimpáticos/fisiopatologia , Regulação da Expressão Gênica , Glândula de Harder/cirurgia , Hiperalgesia/etiologia , Hiperalgesia/genética , Hiperalgesia/metabolismo , Interleucina-18/genética , Interleucina-18/metabolismo , Interleucina-1beta/genética , Interleucina-1beta/metabolismo , Aparelho Lacrimal/cirurgia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neuralgia/etiologia , Neuralgia/genética , Neuralgia/metabolismo , Prostaglandina-E Sintases/genética , Prostaglandina-E Sintases/metabolismo , Canais de Cátion TRPM/antagonistas & inibidores , Canais de Cátion TRPM/metabolismo , Gânglio Trigeminal/efeitos dos fármacos , Gânglio Trigeminal/metabolismo , Gânglio Trigeminal/fisiopatologia
14.
Nutrients ; 12(2)2020 Jan 27.
Artigo em Inglês | MEDLINE | ID: mdl-32012665

RESUMO

Aspartame and Stevia are widely substituted for sugar. Little is known about cerebral activation in response to low-caloric sweeteners in comparison with high-caloric sugar, whereas these molecules lead to different metabolic effects. We aimed to compare gustatory evoked potentials (GEPs) obtained in response to sucrose solution in young, healthy subjects, with GEPs obtained in response to aspartame and Stevia. Twenty healthy volunteers were randomly stimulated with three solutions of similar intensities of sweetness: Sucrose 10 g/100 mL of water, aspartame 0.05 g/100 mL, and Stevia 0.03 g/100 mL. GEPs were recorded with EEG (Electroencephalogram) electrodes. Hedonic values of each solution were evaluated using the visual analog scale (VAS). The main result was that P1 latencies of GEPs were significantly shorter when subjects were stimulated by the sucrose solution than when they were stimulated by either the aspartame or the Stevia one. P1 latencies were also significantly shorter when subjects were stimulated by the aspartame solution than the Stevia one. No significant correlation was noted between GEP parameters and hedonic values marked by VAS. Although sucrose, aspartame, and Stevia lead to the same taste perception, cerebral activation by these three sweet solutions are different according to GEPs recording. Besides differences of taste receptors and cerebral areas activated by these substances, neural plasticity, and change in synaptic connections related to sweet innate preference and sweet conditioning, could be the best hypothesis to explain the differences in cerebral gustatory processing after sucrose and sweeteners activation.


Assuntos
Aspartame , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Stevia , Sacarose , Adulto , Feminino , Humanos , Masculino , Edulcorantes , Percepção Gustatória , Adulto Jovem
15.
Sci Rep ; 9(1): 16673, 2019 11 13.
Artigo em Inglês | MEDLINE | ID: mdl-31723186

RESUMO

Medetomidine has become a popular choice for anesthetizing rats during long-lasting sessions of blood-oxygen-level dependent (BOLD) functional magnetic resonance imaging (fMRI). Despite this, it has not yet been thoroughly established how commonly reported fMRI readouts evolve over several hours of medetomidine anesthesia and how they are affected by the precise timing, dose, and route of administration. We used four different protocols of medetomidine administration to anesthetize rats for up to six hours and repeatedly evaluated somatosensory stimulus-evoked BOLD responses and resting state functional connectivity. We found that the temporal evolution of fMRI readouts strongly depended on the method of administration. Intravenous administration of a medetomidine bolus (0.05 mg/kg), combined with a subsequent continuous infusion (0.1 mg/kg/h), led to temporally stable measures of stimulus-evoked activity and functional connectivity throughout the anesthesia. Deviating from the above protocol-by omitting the bolus, lowering the medetomidine dose, or using the subcutaneous route-compromised the stability of these measures in the initial two-hour period. We conclude that both an appropriate protocol of medetomidine administration and a suitable timing of fMRI experiments are crucial for obtaining consistent results. These factors should be considered for the design and interpretation of future rat fMRI studies.


Assuntos
Mapeamento Encefálico/métodos , Encéfalo/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Hipnóticos e Sedativos/administração & dosagem , Imageamento por Ressonância Magnética/métodos , Medetomidina/administração & dosagem , Animais , Encéfalo/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Feminino , Masculino , Ratos , Ratos Wistar , Descanso/fisiologia
16.
Neuroimage ; 202: 116139, 2019 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-31476429

RESUMO

The presented study investigates the functional role of GABA in somatosensory processing, using a combined neuropharmacological-neuroimaging approach. Three different GABA agonists (GABAA: alprazolam, ethanol; GABAB: baclofen) were investigated in a double blind cross-over design in 16 male participants, accomplishing a tactile perception task. Somatosensory evoked magnetic fields modulated by GABAR-agonists and placebo were recorded using whole-head magnetoencephalography. Peak latencies and amplitudes of primary (SI) and secondary (SII) somatosensory cortex source activities confirmed the previously reported role of GABA as a modulator of somatosensory processing. Significant inhibitory effects on the latency of SII and on the amplitude of SI and SII were found exclusively for alprazolam, a positive allosteric modulator at GABAA receptors. The GABAB agonist baclofen did not have any modulatory effect. Moreover, we investigated whether the observed effects of alprazolam on the level of SII were explainable by the mere propagation of activity from SI to SII modulated by GABAA receptors, independently from any further GABAA-mediated inhibition in SII. By estimating the transfer function between SI and SII activation under placebo conditions, we were able to predict SII activity for the administration of GABA receptors agonists under the assumption that GABA exclusively acts at the level of SI. By comparing measured and predicted data, we propose a model in which the initial activation of SI is modulated through GABAA receptors and subsequently propagated to SII, without any significant further inhibition. In addition, initial GABAA effects in SI appear to be strongly potentiated with time, selectively in SI but not in SII.


Assuntos
Potenciais Somatossensoriais Evocados , Agonistas de Receptores de GABA-A/farmacologia , Agonistas dos Receptores de GABA-B/farmacologia , Magnetoencefalografia , Inibição Neural , Córtex Somatossensorial , Percepção do Tato , Ácido gama-Aminobutírico/fisiologia , Adulto , Alprazolam/farmacologia , Baclofeno/farmacologia , Método Duplo-Cego , Etanol/farmacologia , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/fisiologia , Humanos , Masculino , Inibição Neural/efeitos dos fármacos , Inibição Neural/fisiologia , Córtex Somatossensorial/efeitos dos fármacos , Córtex Somatossensorial/fisiologia , Percepção do Tato/efeitos dos fármacos , Percepção do Tato/fisiologia , Adulto Jovem
17.
Clin Neurophysiol ; 130(10): 1804-1812, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31401489

RESUMO

OBJECTIVE: To elucidate the effects of perampanel (PER) on refractory cortical myoclonus for dose, etiology and somatosensory-evoked potential (SEP) findings. METHODS: We examined 18 epilepsy patients with seizure and cortical myoclonus. Based on data accumulated before and after PER treatment, correlations among clinical scores in myoclonus and activities of daily life (ADL); early cortical components of SEP; and PER blood concentration, were analyzed. RESULTS: PER (mean dose: 3.2 ±â€¯2.1 mg/day) significantly improved seizures, myoclonus and ADL and significantly decreased the amplitude of and prolonged latency of giant SEP components. The degree of P25 and N33 prolongations (23.8 ±â€¯1.6 to 24.7 ±â€¯1.7 ms and 32.1 ±â€¯4.0 to 33.7 ±â€¯3.4 ms) were significantly correlated with improved ADL score (p = 0.019 and p = 0.025) and blood PER concentration (p = 0.011 and p = 0.025), respectively. CONCLUSIONS: Low-dose PER markedly improved myoclonus and ADL in patients with refractory cortical myoclonus. Our results suggest that SEP, particularly P25 latency, can be used as a potential biomarker for assessing the objective effects of PER on intractable cortical myoclonus. SIGNIFICANCE: In this study, PER lessened the degree of synchronized discharges in the postsynaptic neurons in the primary motor cortex.


Assuntos
Anticonvulsivantes/administração & dosagem , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Epilepsias Mioclônicas Progressivas/diagnóstico , Epilepsias Mioclônicas Progressivas/tratamento farmacológico , Piridonas/administração & dosagem , Córtex Sensório-Motor/efeitos dos fármacos , Adulto , Idoso , Relação Dose-Resposta a Droga , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Epilepsias Mioclônicas Progressivas/fisiopatologia , Mioclonia/diagnóstico , Mioclonia/tratamento farmacológico , Mioclonia/fisiopatologia , Nitrilas , Estudos Retrospectivos , Córtex Sensório-Motor/fisiologia , Adulto Jovem
18.
Chem Senses ; 44(8): 583-592, 2019 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-31420672

RESUMO

Published evidence suggests that inherent rhythmically active or "bursting" primary olfactory receptor neurons (bORNs) in crustaceans have the previously undescribed functional property of encoding olfactory information by having their rhythmicity entrained by the odor stimulus. In order to determine whether such bORN-based encoding is a fundamental feature of olfaction that extends beyond crustaceans, we patch-clamped bORN-like ORNs in mice, characterized their dynamic properties, and show they align with the dynamic properties of lobster bORNs. We then characterized bORN-like activity by imaging the olfactory epithelium of OMP-GCaMP6f mice. Next, we showed rhythmic activity is not dependent upon the endogenous OR by patching ORNs in OR/GFP mice. Lastly, we showed the properties of bORN-like ORNs characterized in mice generalize to rats. Our findings suggest encoding odor time should be viewed as a fundamental feature of olfaction with the potential to be used to navigate odor plumes in animals as diverse as crustaceans and mammals.


Assuntos
Cálcio/fisiologia , Potenciais Somatossensoriais Evocados/fisiologia , Odorantes/análise , Neurônios Receptores Olfatórios/fisiologia , Olfato/fisiologia , Animais , Cálcio/análise , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Imagem Molecular , Nephropidae , Mucosa Olfatória/citologia , Mucosa Olfatória/fisiologia , Neurônios Receptores Olfatórios/citologia , Técnicas de Patch-Clamp , Cultura Primária de Células , Ratos , Ratos Sprague-Dawley
19.
Br J Clin Pharmacol ; 85(11): 2512-2523, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31338868

RESUMO

AIMS: Type 1 diabetes can be complicated with neuropathy that involves immune-mediated and inflammatory pathways. Glucagon-like peptide-1 receptor agonists such as liraglutide, have shown anti-inflammatory properties, and thus we hypothesized that long-term treatment with liraglutide induced diminished inflammation and thus improved neuronal function. METHODS: The study was a randomized, double-blinded, placebo-controlled trial of adults with type 1 diabetes and confirmed symmetrical polyneuropathy. They were randomly assigned (1:1) to receive either liraglutide or placebo. Titration was 6 weeks to 1.2-1.8 mg/d, continuing for 26 weeks. The primary endpoint was change in latency of early brain evoked potentials. Secondary endpoints were changes in proinflammatory cytokines, cortical evoked potential, autonomic function and peripheral neurophysiological testing. RESULTS: Thirty-nine patients completed the study, of whom 19 received liraglutide. In comparison to placebo, liraglutide reduced interleukin-6 (-22.6%; 95% confidence interval [CI]: -38.1, -3.2; P = .025) with concomitant numerical reductions in other proinflammatory cytokines. However neuronal function was unaltered at the central, autonomic or peripheral level. Treatment was associated with -3.38 kg (95% CI: -5.29, -1.48; P < .001] weight loss and a decrease in urine albumin/creatinine ratio (-40.2%; 95% CI: -60.6, -9.5; P = .02). CONCLUSION: Hitherto, diabetic neuropathy has no cure. Speculations can be raised whether mechanism targeted treatment, e.g. lowering the systemic level of proinflammatory cytokines may lead to prevention or treatment of the neuroinflammatory component in early stages of diabetic neuropathy. If ever successful, this would serve as an example of how fundamental mechanistic principles are translated into clinical practice similar to those applied in the cardiovascular and nephrological clinic.


Assuntos
Diabetes Mellitus Tipo 1/tratamento farmacológico , Neuropatias Diabéticas/tratamento farmacológico , Incretinas/administração & dosagem , Interleucina-6/sangue , Liraglutida/administração & dosagem , Polineuropatias/tratamento farmacológico , Adulto , Sistema Nervoso Autônomo/efeitos dos fármacos , Sistema Nervoso Autônomo/fisiopatologia , Diabetes Mellitus Tipo 1/sangue , Diabetes Mellitus Tipo 1/complicações , Diabetes Mellitus Tipo 1/imunologia , Neuropatias Diabéticas/diagnóstico , Neuropatias Diabéticas/imunologia , Neuropatias Diabéticas/fisiopatologia , Método Duplo-Cego , Estimulação Elétrica , Eletroencefalografia , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/fisiologia , Feminino , Humanos , Interleucina-6/imunologia , Masculino , Nervo Mediano/efeitos dos fármacos , Nervo Mediano/fisiopatologia , Pessoa de Meia-Idade , Polineuropatias/diagnóstico , Polineuropatias/imunologia , Polineuropatias/fisiopatologia , Estudos Prospectivos , Falha de Tratamento , Redução de Peso/efeitos dos fármacos
20.
Neurol Res ; 41(9): 802-810, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31142218

RESUMO

Objectives:Traumatic spinal cord injury (SCI) is a significant clinical problem with numerous secondary complications and perpetual deficits. No potent treatment is currently available to fully repair motor and other neurological functions. We studied the effects of dantrolene (DNT) at different time points, on the motor-evoked potentials (MEPs) and the apoptosis response in spinal cord injury. Methods:The study was conducted on a total of 38 rabbits divided into five main groups.These were group 1 (sham): only laminectomy (n = 6), group 2 (SCI): laminectomy and traumatic SCI (n = 8), group 3 (DNT 0h): just after the SCI, DNT 10 mg/kg I.P. (n = 8), group 4 (DNT 1h): 1 h after the SCI, DNT 10 mg/kg I.P. (n = 8), and group 5 (DNT 4h): 4 h after the SCI, DNT 10 mg/kg I.P. (n = 8). Results: DNT, which was administered as the treatment, had a therapeutic effect on the motor function. This effect was observed by recording neural transmission obtained via the Tarlov test and a transcranial magnetic stimulator by using the values of the MEPs. A significant decrease was histopathologically observed in the apoptotic cell count. Discussion: The electrophysiological efficacy of our model of trauma as SCI has been complemented with the significant differences between the control group and the SCI group. This creates a need for electrophysiological studies to be conducted in the future because effects, even at a minimum level, may play an important role in finding an applicable medicine for SCI.


Assuntos
Dantroleno/farmacologia , Potencial Evocado Motor/efeitos dos fármacos , Traumatismos da Medula Espinal/tratamento farmacológico , Medula Espinal/efeitos dos fármacos , Animais , Apoptose/efeitos dos fármacos , Modelos Animais de Doenças , Potencial Evocado Motor/fisiologia , Potenciais Somatossensoriais Evocados/efeitos dos fármacos , Potenciais Somatossensoriais Evocados/fisiologia , Laminectomia/métodos , Coelhos , Estimulação Magnética Transcraniana
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