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Resumen La patología del sistema nervioso central, habitualmente, no provoca síntomas auditivos unilaterales, ya que la vía auditiva central está formada por una red de conexiones cruzadas entre los diferentes núcleos que la forman. Además, hay que considerar que una lesión pequeña puede extenderse a más de una estructura provocando varios déficits neurológicos debido a la proximidad de los tractos y núcleos nerviosos. Las lesiones unilaterales circunscritas en el colículo inferior son infrecuentes. No obstante, se han descrito casos en los que lesiones unilaterales de diversas etiologías en esta localización causaban síntomas auditivos. Ya que la vía auditiva central es cruzada, síntomas auditivos detectados con más frecuencia afectaban concretamente a la capacidad de localización del sonido o la comprensión verbal. Presentamos el caso de un hombre de 44 años con acúfeno unilateral derecho de larga evolución, sin otra clínica asociada quien fue diagnosticado de un tumor en el colículo inferior derecho mediante resonancia magnética cerebral. Se exponen los hallazgos clínicos y radiológicos del caso.
Abstract Central nervous system diseases usually do not cause auditory symptoms because the central auditory pathway consists on a network of crossed connections between the different nuclei that form it. In addition, we must consider that a small lesion might extend to more than one structure producing many neurologic symptoms due to the proximity of tracts and nuclei in the midbrain. Unilateral circumscribed lesions at inferior colliculus are rare. Nevertheless, lesions at this location causing auditory symptoms have been described. Because of the crossed central auditory pathway, the most commonly detected auditory symptoms specifically affected the ability to locate sound or verbal comprehension. We present the case of a 44-year-old man with a long-term monoaural right-sided tinnitus without other complaints who was diagnosed of a tumour at right inferior colliculus by neuroimaging. Clinical and radiological findings of this case are discussed.
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Humans , Male , Adult , Tinnitus/complications , Inferior Colliculi/pathology , Magnetic Resonance Spectroscopy , Central Nervous System Diseases , NeoplasmsABSTRACT
Objective:To investigate the local consistency of inferior colliculus and ventrolateral orbital cortex by resting-state functional magnetic resonance imaging (fMRI) in rats with noise induced deafness and its relationship with anxiety- and depression-like behavior.Methods:Twenty-four clean grade male four-weeks old SD rats were randomly divided into noise group and control group with 12 rats in each group.Rats in the noise group were exposed to 122 dB broadband strong noise for 2 hours to induce severe bilateral hearing loss, while rats in the control group were placed in a quiet environment. Hearing thresholds were assessed by auditory brainstem response (ABR) test. The open field test (OFT) was conducted to examine anxiety-depression related behavior, and the local consistency in the rat brain was evaluated by fMRI.SPM12 software was used to process fMRI data, and Pearson correlation analysis was conducted by SPSS 22.0 software to calculate the correlation between fMRI data and behavior.Results:The results of ABR showed that the full band hearing threshold of rats in the noise group was higher than that of rats in the control group ((85.417±6.463) dB, (20.083±8.853) dB, t=46.168, P<0.001). And compared with control group, the rats in the noise group showed obvious anxiety-depression-like behavior in the open field test, that was, low activity level.The results of OFT showed that the total distance ((39.912±5.696) m, (47.993±10.820)m, t=-2.289, P=0.032), average moving speed ((13.306±1.900)cm/s, (15.998±3.607)cm/s, t=-2.290, P=0.032) and standing times ((13.333±5.960), (23.500±7.323), t=-3.730, P=0.001) of the rats in the noise group were all lower than those in the control group. Compared with the control group, the local consistency of hypothalamus in the noise group was significantly enhanced, while the local consistency of ventrolateral orbital cortex was significantly reduced, and the abnormal neural activity was lateralized. The correlation analysis showed that the neural activity of the inferior colliculus was negatively correlated with the total distance of rats in the noise group moving in the open field( r=-0.691, P=0.013), while the neural activity of the ventrolateral orbital cortex was not significantly correlated with the anxiety-depression-like behavior in the open field. Conclusions:The neural activity of inferior colliculus is closely related to anxious-depression behavior in rats with noise-induced deafness, while the ventrolateral orbital cortex may be related with other behaviors.
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Environmental threats often trigger innate defensive responses in mammals. However, the gradual development of functional properties of these responses during the postnatal development stage remains unclear. Here, we report that looming stimulation in mice evoked flight behavior commencing at P14-16 and had fully developed by P20-24. The visual-evoked innate defensive response was not significantly altered by sensory deprivation at an early postnatal stage. Furthermore, the percentages of wide-field and horizontal cells in the superior colliculus were notably elevated at P20-24. Our findings define a developmental time window for the formation of the visual innate defense response during the early postnatal period and provide important insight into the underlying mechanism.
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Animals , Mice , Evoked Potentials, Visual , Fear/physiology , Mammals , Mice, Inbred C57BL , Neurons/physiology , Superior Colliculi/physiologyABSTRACT
Spontaneous activity in the brain maintains an internal structured pattern that reflects the external environment, which is essential for processing information and developing perception and cognition. An essential prerequisite of spontaneous activity for perception is the ability to reverberate external information, such as by potentiation. Yet its role in the processing of potentiation in mouse superior colliculus (SC) neurons is less studied. Here, we used electrophysiological recording, optogenetics, and drug infusion methods to investigate the mechanism of potentiation in SC neurons. We found that visual experience potentiated SC neurons several minutes later in different developmental stages, and the similarity between spontaneous and visually-evoked activity increased with age. Before eye-opening, activation of retinal ganglion cells that expressed ChR2 also induced the potentiation of spontaneous activity in the mouse SC. Potentiation was dependent on stimulus number and showed feature selectivity for direction and orientation. Optogenetic activation of parvalbumin neurons in the SC attenuated the potentiation induced by visual experience. Furthermore, potentiation in SC neurons was blocked by inhibiting the glutamate transporter GLT1. These results indicated that the potentiation induced by a visual stimulus might play a key role in shaping the internal representation of the environment, and serves as a carrier for short-term memory consolidation.
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Rapid detection and response to visual threats are critical for survival in animals. The amygdala (AMY) is hypothesized to be involved in this process, but how it interacts with the visual system to do this remains unclear. By recording flash-evoked potentials simultaneously from the superior colliculus (SC), lateral posterior nucleus of the thalamus, AMY, lateral geniculate nucleus (LGN) and visual cortex, which belong to the cortical and subcortical pathways for visual fear processing, we investigated the temporal relationship between these regions in visual processing in rats. A quick flash-evoked potential (FEP) component was identified in the AMY. This emerged as early as in the LGN and was approximately 25 ms prior to the earliest component recorded in the SC, which was assumed to be an important area in visual fear. This quick P1 component in the AMY was not affected by restraint stress or corticosterone injection, but was diminished by RU38486, a glucocorticoid receptor blocker. By injecting a monosynaptic retrograde AAV tracer into the AMY, we found that it received a direct projection from the retina. These results confirm the existence of a direct connection from the retina to the AMY, that the latency in the AMY to flashes is equivalent to that in the sensory thalamus, and that the response is modulated by glucocorticoids.
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Objective: To explore the necessity of repairing the deep layer of deltoid ligament in the treatment of mixed medial injury associated with ankle fractures. Methods: Between January 2016 and December 2018, 12 patients with mixed medial injury associated with ankle fractures were treated with the fixation of the lateral malleolus by bone plates, the fixation of the anterior colliculus of medial malleolus by cannulated screws, and the repair of the deltoid ligament by suture anchors. There were 8 males and 4 females, with an average age of 42 years (range, 18-56 years). According to the Lauge-Hansen classification criteria, there were 11 cases of supination-external rotation type and 1 case of pronation-external rotation type. According to the Weber classification criteria, all cases were type B. The time from injury to operation was 3-6 days, with an average of 4.7 days. In each patient, X-ray films of anteroposterior and lateral views and mortise view of ankle were taken postoperatively. The motion range of ankle joints was observed. The function of the ankle and the outcome of the treatment were evaluated according to the American Orthopaedic Foot and Ankle Society (AOFAS) scoring system, Olerud-Molander scoring system, and the visual analogue scale (VAS) score. Results: All cases were followed up 12-42 months (mean, 28 months). The 12 patients returned to their pre-injury jobs. Five patients with sports injury completely recovered to their pre-injury motor function. No patient experienced persistent medial ankle pain or ankle instability. At last follow-up, the ankle range of motion in dorsiflexion was 9°-25° (mean, 17.96°), which was 0°-11° (mean, 4.02°) less than that in normal side; the range of motion in plantar flexion was 38°-50° (mean, 43.90°), which was 0°-7° (mean, 2.53°) less than that in normal side. The AOFAS score was 88-100 (mean, 96.7); the Olerud-Molander score was 90-100 (mean, 96.5); the VAS score was 0-3 (mean, 1.1). Conclusion: It is necessary to repair the deep layer of deltoid ligament in the mixed medial injuries associated with ankle fracture, which include anterior colliculus fracture and deep deltoid ligament injury. A better outcome can be achieved by employing the suture anchor repair method.
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OBJECTIVES.: Sodium salicylate (SS) is well known for its ototoxic properties that induce functional and morphological changes in the cochlea and brain. Ginkgo biloba extract (GBE) has been widely used for treatment of various neurodegenerative diseases; however, its effects on salicylate-induced ototoxicity remain unclear. Herein, we examined the effects of EGb 761 (EGb), a standard form of GBE, on the plasticity of the N-methyl-D-aspartate receptor subunit 2B (GluN2B) in the inferior colliculus (IC) following SS administration. METHODS.: Seven-week-old Sprague Dawley rats (n=24) were randomly allocated to control, SS, EGb, and EGb+SS groups. The SS group received a single intraperitoneal SS injection (350 mg/kg), the EGb group received EGb orally for 5 consecutive days (40 mg/kg), and the EGb+SS group received EGb for 5 consecutive days, followed by an SS injection. The auditory brainstem responses (ABRs) were assessed at baseline and 2 hours after SS administration. GluN2B expression was examined by Western blot and immunohistochemistry. RESULTS.: There were no significant differences in ABR threshold shifts among the groups. The expression of the GluN2B protein normalized by which of glyceraldehyde 3-phosphate dehydrogenase (GAPDH) was significantly lower in the EGb+SS group, as compared to the SS group (P=0.012). Weak and diffused GluN2B immunoreactivity was detected in the IC neural cells of the EGb+SS group, while those of the SS group exhibited strong and diffused GluN2B positivity. CONCLUSION.: EGb may play a role in regulating the GluN2B expression in the IC of salicylate-induced ototoxicity model.
Subject(s)
Blotting, Western , Brain , Cochlea , Evoked Potentials, Auditory, Brain Stem , Ginkgo biloba , Glyceraldehyde 3-Phosphate , Immunohistochemistry , Inferior Colliculi , N-Methylaspartate , Neurodegenerative Diseases , Oxidoreductases , Plastics , Rats, Sprague-Dawley , Sodium SalicylateABSTRACT
Objective To study the possible mechanism of hearing impairment after noise exposure .Methods Adult SD rats (n=14) were monaurally exposed to a loud noise (16 kHz ,one octave band pass (116 dB SPL)) for 1-hour ,or left as non-exposed controls (n=8) .The ABR was measured before and on the 7th day following unilateral noise exposure .All the Animals were euthanased at 7th day following acoustic trauma .We used Western blots to quantify protein levels of PV ,CR and CB in the inferior colliculus .Results The auditory thresholds in 8 , 12 ,16 ,20 ,24 ,and 32 kHz of all the ears exposed to noise showed a significant increase (P<0 .001) .Compared to the sham -exposed controls ,noise-exposed animals had significantly higher levels of PV and CR and lower levels of CB in both the ipsilateral and contralateral IC than controls (P<0 .05) .Respectively ,all the noise-exposed ani-mals had higher levels of PV and CR in the ipsilateral IC than ipsilateral side (P<0 .05) .Conclusion These studies display a significant threshold shift and changes on the expressions of PV ,CR and CB in IC following acoustic trau-ma ,which may be related to noise deafness ,tinnitus and other series of auditory dysfunction .
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Abstract Introduction: Salicylate at high doses induces tinnitus in humans and experimental animals. However, the mechanisms and loci of action of salicylate in inducing tinnitus are still not well known. The expression of Immediate Early Genes (IEG) is traditionally associated with long-term neuronal modifications but it is still not clear how and where IEGs are activated in animal models of tinnitus. Objectives: Here we investigated the expression of c-fos and Egr-1, two IEGs, in the Dorsal Cochlear Nucleus (DCN), the Inferior Colliculus (IC), and the Posterior Ventral Cochlear Nucleus (pVCN) of rats. Methods: Rats were treated with doses known to induce tinnitus in rats (300 mg/kg i.p. daily, for 3 days), and c-fos and Egr-1 protein expressions were analyzed using western blot and immunocytochemistry. Results: After administration of salicylate, c-fos protein expression increased significantly in the DCN, pVCN and IC when assayed by western blot. Immunohistochemistry staining showed a more intense labeling of c-fos in the DCN, pVCN and IC and a significant increase in c-fos positive nuclei in the pVCN and IC. We did not detect increased Egr-1 expression in any of these areas. Conclusion: Our data show that a high dose of salicylate activates neurons in the DCN, pVCN and IC. The expression of these genes by high doses of salicylate strongly suggests that plastic changes in these areas are involved in the genesis of tinnitus.
Resumo Introdução: Salicilato em doses elevadas induz zumbido nos seres humanos e em animais experimentais. No entanto, os mecanismos e loci de ação do salicilato na indução de zumbido ainda não são bem conhecidos. A expressão dos genes precoces imediatos (GPIs) está tradicionalmente associada a alterações neuronais em longo prazo, mas ainda não está claro como e onde os GPIs são ativados em modelos animais de zumbido. Objetivos: No presente estudo investigamos a expressão de c-fos e Egr-1, dois GPIs, no núcleo coclear dorsal (NCD), colículo inferior (CI) e núcleo coclear ventral posterior (NCVp) de ratos. Métodos: Os ratos foram tratados com doses que, conhecidamente, induzem zumbido em ratos (300 mg/kg IP/dia, por três dias) e as expressões das proteínas c-fos e Egr-1 foram analisadas por meio de Western blot e imunoistoquímica. Resultados: Após a administração de salicilato, a expressão da proteína c-fos aumentou significativamente no NCD, NCVp e CI, quando analisados por Western blot. A coloração imunoistoquímica mostrou uma marcação mais intensa de c-fos no NCD, NCVp e CI e um aumento significativo de núcleos positivos de c-fos no NCVp e CI. Não detectamos aumento da expressão de Egr-1 em qualquer dessas áreas. Conclusão: Nossos dados mostram que uma dose alta de salicilato ativa neurônios no NCD, NCVp e CI. A expressão desses genes por doses altas de salicilato sugere que as alterações plásticas nessas áreas estão envolvidas na gênese do zumbido.
Subject(s)
Animals , Male , Rats , Inferior Colliculi/drug effects , Salicylates/pharmacology , Gene Expression Regulation/drug effects , Genes, Immediate-Early/drug effects , Cochlear Nucleus/drug effects , Salicylates/administration & dosage , Blotting, Western , Genes, fos/drug effects , Rats, Wistar , Dose-Response Relationship, Drug , Early Growth Response Protein 1/drug effectsABSTRACT
Objective To investigate the influences of sodium salicylate on the auditory brainstem response (ABR)and expression of EphA4mRNA in rat inferior colliculus and its effects on salicylate ototoxicity.Methods A total of 30 healthy SPF rats were randomly divided into five groups:the control group (without any treatment),S7 (i.m.injection of sodium salicylate,175mg/kg,twice daily for 7 days),S14(the same method as S7,twice daily for 14 days),S14+R14(the same method as S14,twice daily for 14 days and recovered for 14 days),and S14+R28(the same method as S14,twice daily for 14 days and recovered for 28 days).After the ABR assessment,rats were sacri-ficed after deep anesthesia and the inferior colliculus tissues were dissected.Real-time PCR was used to detect the expression of EphA4mRNA.Results Compared with the control group,ABR thresholds in the S7 group and S14 group were increased significantly (P0.05).The inferior colliculus EphA4mRNA expression level of S7 group was signifi-cantly decreased than the control group (P0.05).Conclusion Long term injection of sodium salicylate can cause changes in the inferior colliculus of EphA4mRNA which are related closely with synaptic plasticity.It may lead the alteration of the inferior colliculus synaptic plasticity,which is associated with the changes of the hearing failure and the tinni-tus behavior.This indicates that EphA4 which is considered as a related protein in the inferior colliculus may play an important role in the pathology of tinnitus.
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Objective To investigate the effect of impulse noise expose on the expression of growth associated protein 43(Gap-43) in inferior colliculus in rat.Methods SPF grade Male SD rats were randomly divided into 5 groups.The normal control group received noise exposure.The model groups received an averange impulse noise exposure of 156 dB SPL with a pulse duration of 0.23 ms, once for 6 s, for 50 times.Auditory brainstem responses (ABRs) were measured before and 3,7,14, and 28 d after noise exposure with tone pips of 2,4,8,16, and 32 kHz, from 20 to 110 dB SPL.Bilateral inferior colliculus of rats in the model groups was collected and treated by immunohistochemical staining.Gap-43 expression of rats in different groups was measured by determining the gray value of inferior immunohistochemical images.Results After noise exposure, ABRs threshold in the model groups were significantly higher than those of in the normal group (P<0.05 or P<0.01).ABRs threshold at 14 and 28 days after noise exposure were significantly lower than 3 days after impulse exposure (P<0.05).Expression of Gap-43 in inferior colliculus was significantly up-regulated in the noise exposed groups compared with the normal group (P<0.05 or P<0.01).Expression of Gap-43 was significantly down-regulated 28 days after noise expose compared with 3 days after noise expose(P<0.05).Conclusion Impulse noise exposure leads to significant elevation of ABR thresholds and up-regulation of Gap-43 expression in inferior colliculus.Impulse noise exposure may induce auditory cortex prominent remodeling.
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The circling mice with tmie gene mutation are known as an animal deafness model, which showed hyperactive circling movement. Recently, the reinvestigation of circling mouse was performed to check the inner ear pathology as a main lesion of early hearing loss. In this trial, the inner ear organs were not so damaged to cause the hearing deficit of circling (cir/cir) mouse at 18 postnatal day (P18) though auditory brainstem response data indicated hearing loss of cir/cir mice at P18. Thus, another mechanism may be correlated with the early hearing loss of cir/cir mice at P18. Hearing loss in the early life can disrupt the ascending and descending information to inferior colliculus (IC) as integration site. There were many reports that hearing loss could result in the changes in Ca²⁺ concentration by either cochlear ablation or genetic defect. However, little was known to be reported about the correlation between the pathology of IC and Ca²⁺ changes in circling mice. Therefore, the present study investigated the distribution of calcium-binding proteins (CaBPs), calbindin-D28k, parvalbumin, and calretinin immunoreactivity (IR) in the IC to compare among wild-type (+/+), heterozygous (+/cir), and homozygous (cir/cir) mice by immunohistochemistry. The decreases of CaBPs IR in cir/cir were statistically significant in the neurons as well as neuropil of IC. Thus, this study proposed overall distributional alteration of CaBPs IR in the IC caused by early hearing defect and might be helpful to elucidate the pathology of central auditory disorder related with Ca²⁺ metabolism.
Subject(s)
Animals , Mice , Calbindin 1 , Calbindin 2 , Calcium-Binding Proteins , Deafness , Ear, Inner , Evoked Potentials, Auditory, Brain Stem , Hearing , Hearing Loss , Immunohistochemistry , Inferior Colliculi , Metabolism , Neurons , Neuropil , Parvalbumins , PathologyABSTRACT
OBJECTIVE To study the proteome of inferior colliculus and determinate the region-typical proteins which may be the candidate cause of the Central Auditory Processing Disorders. METHODS The telencephalon was taken as reference, and then identified and quantified the proteome of IC of adult rats with iTRAQ. Those with higher abundance in inferior colliculus than the other three regions were considered as IC-Region typical proteins,which may lead to functional specializations. RESULTS We identified 1937 cytomembrane proteins in total, among which there are 53 IC-Region typical proteins, which may lead to functional specializations of inferior colliculus.We used GO and KEGG pathway to analyze these proteins and then found that these proteins mainly take part in the regulation of neurons development and information integrations. CONCLUSION Our quantitative comparison of inferior colliculus has revealed two candidate proteins, including CaMKII and SV2A, which may play important roles in maintaining the balance of excitatory and inhibitory transmitters release. These proteins may be the candidate proteins for Central Auditory Processing Disorders.
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PURPOSE: Several morphometric studies have been performed to investigate brain abnormalities in congenitally deaf people. But no report exists concerning structural brain abnormalities in congenitally deaf adolescents. We evaluated the regional volume changes in gray matter (GM) using voxel-based morphometry (VBM) in congenitally deaf adolescents. MATERIALS AND METHODS: A VBM8 methodology was applied to the T1-weighted magnetic resonance imaging (MRI) scans of eight congenitally deaf adolescents (mean age, 15.6 years) and nine adolescents with normal hearing. All MRI scans were normalized to a template and then segmented, modulated, and smoothed. Smoothed GM data were tested statistically using analysis of covariance (controlled for age, gender, and intracranial cavity volume). RESULTS: The mean values of age, gender, total volumes of GM, and total intracranial volume did not differ between the two groups. In the auditory centers, the left anterior Heschl's gyrus and both inferior colliculi showed decreased regional GM volume in the congenitally deaf adolescents. The GM volumes of the lingual gyri, nuclei accumbens, and left posterior thalamic reticular nucleus in the midbrain were also decreased. CONCLUSIONS: The results of the present study suggest that early deprivation of auditory stimulation in congenitally deaf adolescents might have caused significant underdevelopment of the auditory cortex (left Heschl's gyrus), subcortical auditory structures (inferior colliculi), auditory gain controllers (nucleus accumbens and thalamic reticular nucleus), and multisensory integration areas (inferior colliculi and lingual gyri). These defects might be related to the absence of general auditory perception, the auditory gating system of thalamocortical transmission, and failure in the maturation of the auditory-to-limbic connection and the auditorysomatosensory-visual interconnection.
Subject(s)
Adolescent , Humans , Acoustic Stimulation , Auditory Cortex , Auditory Perception , Brain , Hearing , Inferior Colliculi , Magnetic Resonance Imaging , MesencephalonABSTRACT
Objective To study the changes of the expression of growth associated protein -43(GAP 43) in cochlear nucleus and the inferior colliculus (IC) in rats after unilateral cochlear damage at different time points after surgery ,and explore the remodeling and repair process of synapse in brainstem auditory center of rats after auditory deprivation .Methods Thirty rats were randomly divided into six groups :the 3 ,7 ,15 ,30 ,60 days group (with u-nilateral cochlea damage) and the control group (without cochlea damage) with 5 rats in each group .The immuno-histochemical SP method was used to detect the expression of GAP -43 in cochlear nucleus and inferior colliculus at different time points after cochlea damaged in the control group .Results After the unilateral cochlear ear was dam-aged at 3 ,7 ,15 days ,GAP -43 in operation side cochlear nucleus were expressed and the expression level signifi-cantly increased compared with normal control group .After 30 days postoperatively ,GAP - 43 expression level decreased ,but it was still higher than normal control group .After 60 days postoperatively ,GAP - 43 expression level was slightly higher than that of normal control group .After 3 days postoperatively ,GAP - 43 expression level was higher than normal control group .After 7 ,15 days postoperatively ,expression levels were increased .After 30 , 60 days postoperatively ,the expressions gradually decreased ,but still higher than the normal control group .Conclusion After unilateral cochlea damaged ,GAP - 43 was expressed an obvious dynamic change process in cochlear nucleus and infe-rior colliculus .It may reflect the axonal regeneration and synaptic plasticity after hearing loss in brainstem auditory neurons .
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Objective To observe the effects of long term injection sodium salicylate on the auditory brain-stem response(ABR)and expression of glutamic acid decarboxylase -67(GAD67) in rat inferior colliculus .Methods Eighteen healthy Wistar rats were randomly divided into three groups :the sodium salicylate group (intramuscular injection of 10% sodium salicylate ,175 mg/kg ,twice daliy for 28 days) ,the saline group (intramuscular injection with saline on same does at the same time) ,the control group (without any treatment) .The rats received ABR after modeling ,then were decapitated and inferior colliculus tissues were stripped .Western blot was used to study the dif-ferent expression of GAD67 protein levels in the three groups .Results Compared with the saline group and control group ,ABR thresholds of the sodium salicylate group were significantly elevated and latency of wave Ⅲ was aslo sig-nificantly prolonged(P0 .05) .The inferior colliculus GAD67 protein expression level of sodium salicylate group was significantly higher than the saline group and control group(P0 .05) .Conclusion Long term injection of sodium salicylate can cause a change in the inferior colliculus of GAD67 protein expression and the up regulation of GAD67 expression may occur as a com-pensatory response to increase inhibiting effect .The change of GAD67 protein expression is likely as a compensatory and regulatory mechanisms for sodium salicylate ototoxicity .
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Objective To evaluate effect of propofol on the first spike latency-amplitude curve of rat inferior colliculus neurons and to find out mechanisms that propofol leds to the disappearance of auditory nerve electrophysiological .Methods 43 healthy specefic pathogen free(SPF) grade sprague dawley(SD) rats(weighing 200-250 g) were used to established wakeful animal models by ventilating with animal respirator after infusing vecuronium .A microelectrode was penetrated in the inferior colliculus (IC) ,and then research first spike latency-amplitude(FSL-A) using a Tucker-Davis Technologies System 3(TDT3) before and after intraper-itoneal injection of propofol 100 mg/kg of each 10 minutes interval .Results CFs ranging from 2 .5 to 44 kHz .An acoustic response of neurons showed offset response ,the remaining 42 neurons showed onset response .r2 of FSL-A curve equations are significant difference between administered propofol before and after 10 minutes(P<0 .05) ,all of them are larger than 0 .95(P<0 .05) .FSL-A curve after administration can shift the lower curve and coincident with the previous administration in the same rat .Conclusion Propofol affect auditory information transmission by convert localization of FSL-A curve of rat inferior colliculus neurons ,but does not change the meaning of the information encoded .
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The effects of chronic administration of efavirenz commonly used as part of highly active antiretroviral therapy (HAART) for the treatment of Human Immunodeficiency Virus (HIV) type-1 therapy on the chromatophilic substance of the intracranial auditory relay centre namely the inferior colliculus and medial geniculate body of adult wistar rats were carefully studied. The rats of both sexes (n=20), with an average weight of 200g were randomly assigned into treatment (n=10) and control (n=10) groups. The rats in the treatment group received 600 mg/70kg body weight of efavirenz dissolved in distilled water daily for 30 days through the orogastric tube. The control group received equal volume of distilled water daily for 30 days through the same route. The rats were fed with grower's mash obtained from Edo Feeds and Flour Mill Limited, Ewu, Edo state, Nigeria and given water liberally. The rats were sacrificed by cervical dislocation method on the thirty-first day of the experiment. The inferior colliculus and medial geniculate body were carefully dissected out and quickly fixed in 10 percent formal saline for histological study. The histological findings indicated that the treated sections of the inferior colliculus and medial geniculate body showed that the chromatophilics substances were less intensely stained as compared to the control. The parenchyme was vacuolated and with evidence of hypertrophy and more spaces between the axonal mesh around the sparsely distributed neurons as compared to the control group. The treated section of the inferior colliculus showed neurons with faintly stained chromatophilics substances in large, medium and small sized neurons while that of the medial geniculate body showed less intense and enlarge chromatophilics substances with some vacuolations. Chronic administration of efavirenz may therefore have an adverse effect on the chromatophilics substances of the inferior colliculus and medial geniculate body of adult wistar rats...
Fueron estudiados los efectos de la administración crónica del efavirenz, comúnmente utilizado como parte del tratamiento antirretroviral de gran actividad para el VIH tipo 1, sobre la sustancia cromatofílica del centro de relevo auditivo intracraneal, el colículo inferior y cuerpo geniculado medial, en ratas Wistar adultas. Ratas de ambos sexos (n = 20), con un peso promedio de 200g fueron asignadas aleatoriamente a tratamiento (n = 10) y control (n = 10). Las ratas del grupo tratado recibieron 600mg/70kg peso corporal de efavirenz disuelto en agua destilada durante 30 días a través de sonda orogástrica. El grupo de control recibió un volumen igual de agua destilada durante 30 días por la misma vía. Las ratas fueron alimentadas con puré agricultor obtenido de Edo Feeds and Flour Mill Limited, Ewu, estado de Edo, Nigeria y agua ad-libitum. Las ratas se sacrificaron por dislocación cervical el día 31. El colículo inferior y el cuerpo geniculado medial fueron disecados cuidadosamente y se fijaron en solución de formalina salina al 10 por ciento. Los hallazgos histológicos indicaron que en las secciones tratadas del colículo inferior y el cuerpo geniculado medial la sustancia cromatofílica fue menos intensamente teñidas en comparación con el control. El parénquima se vacuoló, con evidencia de hipertrofia y más espacios entre la red axonal alrededor de neuronas escasamente distribuidas en comparación con el grupo control. La sección tratada del colículo inferior mostró neuronas con sustancia cromatofílica débilmente teñida en las neuronas de tamaño grande, mediano y pequeño, mientras que las del cuerpo geniculado medial mostraron sustancia cromatofílica menos intensa, con algunas vacuolaciones amplias. La administración crónica de efavirenz puede tener un efecto adverso sobre las sustancias cromatofílica del colículo inferior y del cuerpo geniculado medial de ratas Wistar adultas. Se recomienda realizar estudios adicionales...
Subject(s)
Animals , Rats , Benzoxazines/pharmacology , Inferior Colliculi , Inferior Colliculi/pathology , Geniculate Bodies , Geniculate Bodies/pathology , Benzoxazines/adverse effects , Rats, WistarABSTRACT
To investigate why the development of a completely circular striated sphincter is so rare, we examined histological sections of 11 female and 11 male mid-term human fetuses. In male fetuses, the striated muscle initially extended in the frontal, rather than in the horizontal plane. However, a knee-like portion was absent in the female fetal urethra because, on the inferior side of the vaginal end, a wide groove for the future vestibule opened inferiorly. Accordingly, it was difficult for the developing striated muscle to surround the groove, even though there was not a great difference in width or thickness between the female vestibule and the male urethra. The development of a completely circular striated sphincter seems to be impossible in females because of interruption of the frontal plane by the groove-like vestibule. However, we cannot rule out the possibility that before descent of the vagina, the urethral striated muscle extends posteriorly.
Subject(s)
Female , Humans , Male , Fetus , Muscle, Striated , Urethra , VaginaABSTRACT
To investigate why the development of a completely circular striated sphincter is so rare, we examined histological sections of 11 female and 11 male mid-term human fetuses. In male fetuses, the striated muscle initially extended in the frontal, rather than in the horizontal plane. However, a knee-like portion was absent in the female fetal urethra because, on the inferior side of the vaginal end, a wide groove for the future vestibule opened inferiorly. Accordingly, it was difficult for the developing striated muscle to surround the groove, even though there was not a great difference in width or thickness between the female vestibule and the male urethra. The development of a completely circular striated sphincter seems to be impossible in females because of interruption of the frontal plane by the groove-like vestibule. However, we cannot rule out the possibility that before descent of the vagina, the urethral striated muscle extends posteriorly.