RESUMO
Noncompetitive N-methyl-D-aspartate/glutamate receptor (NMDAR) antagonists contribute to the pathophysiology of schizophrenia and mood disorders but improve monoaminergic antidepressant-resistant mood disorder and suicidal ideation. The mechanisms of the double-edged sword clinical action of NMDAR antagonists remained to be clarified. The present study determined the interaction between the NMDAR antagonist (MK801), α1 adrenoceptor antagonist (prazosin), and α2A adrenoceptor agonist (guanfacine) on mesocortical and mesothalamic catecholaminergic transmission, and thalamocortical glutamatergic transmission using multiprobe microdialysis. The inhibition of NMDAR in the locus coeruleus (LC) by local MK801 administration enhanced both the mesocortical noradrenergic and catecholaminergic coreleasing (norepinephrine and dopamine) transmissions. The mesothalamic noradrenergic transmission was also enhanced by local MK801 administration in the LC. These mesocortical and mesothalamic transmissions were activated by intra-LC disinhibition of transmission of γ-aminobutyric acid (GABA) via NMDAR inhibition. Contrastingly, activated mesothalamic noradrenergic transmission by MK801 enhanced intrathalamic GABAergic inhibition via the α1 adrenoceptor, resulting in the suppression of thalamocortical glutamatergic transmission. The thalamocortical glutamatergic terminal stimulated the presynaptically mesocortical catecholaminergic coreleasing terminal in the superficial cortical layers, but did not have contact with the mesocortical selective noradrenergic terminal (which projected terminals to deeper cortical layers). Furthermore, the α2A adrenoceptor suppressed the mesocortical and mesothalamic noradrenergic transmissions somatodendritically in the LC and presynaptically/somatodendritically in the reticular thalamic nucleus (RTN). These discrepancies between the noradrenergic and catecholaminergic transmissions in the mesocortical and mesothalamic pathways probably constitute the double-edged sword clinical action of noncompetitive NMDAR antagonists.
Assuntos
Maleato de Dizocilpina/administração & dosagem , Guanfacina/administração & dosagem , Locus Cerúleo/metabolismo , Prazosina/administração & dosagem , Receptores de N-Metil-D-Aspartato/metabolismo , Animais , Córtex Cerebral/metabolismo , Maleato de Dizocilpina/farmacologia , Dopamina/metabolismo , Guanfacina/farmacologia , Hipotálamo/metabolismo , Locus Cerúleo/efeitos dos fármacos , Masculino , Microdiálise/instrumentação , Norepinefrina/metabolismo , Prazosina/farmacologia , Ratos , Transmissão Sináptica/efeitos dos fármacosRESUMO
Brain interstitial fluid drainage and extracellular space are closely related to waste clearance from the brain. Different anesthetics may cause different changes of brain interstitial fluid drainage and extracellular space but these still remain unknown. Herein, effects of the inhalational isoflurane, intravenous sedative dexmedetomidine and pentobarbital sodium on deep brain matters' interstitial fluid drainage and extracellular space and underlying mechanisms were investigated. When compared to intravenous anesthetic dexmedetomidine or pentobarbital sodium, inhalational isoflurane induced a restricted diffusion of extracellular space, a decreased extracellular space volume fraction, and an increased norepinephrine level in the caudate nucleus or thalamus with the slowdown of brain interstitial fluid drainage. A local administration of norepinephrine receptor antagonists, propranolol, atipamezole and prazosin into extracellular space increased diffusion of extracellular space and interstitial fluid drainage whilst norepinephrine decreased diffusion of extracellular space and interstitial fluid drainage. These findings suggested that restricted diffusion in brain extracellular space can cause slowdown of interstitial fluid drainage, which may contribute to the neurotoxicity following the waste accumulation in extracellular space under inhaled anesthesia per se.
Assuntos
Anestésicos Inalatórios/administração & dosagem , Dexmedetomidina/administração & dosagem , Líquido Extracelular/efeitos dos fármacos , Espaço Extracelular/efeitos dos fármacos , Hipnóticos e Sedativos/administração & dosagem , Isoflurano/administração & dosagem , Pentobarbital/administração & dosagem , Administração por Inalação , Administração Intravenosa , Animais , Transporte Biológico , Encéfalo , Núcleo Caudado/metabolismo , Drenagem , Humanos , Imidazóis/administração & dosagem , Masculino , Norepinefrina/metabolismo , Prazosina/administração & dosagem , Propranolol/administração & dosagem , Ratos Sprague-Dawley , Tálamo/metabolismoRESUMO
Degeneration and loss of lower motor neurons is the major pathological hallmark of spinal muscular atrophy (SMA), resulting from low levels of ubiquitously-expressed survival motor neuron (SMN) protein. One remarkable, yet unresolved, feature of SMA is that not all motor neurons are equally affected, with some populations displaying a robust resistance to the disease. Here, we demonstrate that selective vulnerability of distinct motor neuron pools arises from fundamental modifications to their basal molecular profiles. Comparative gene expression profiling of motor neurons innervating the extensor digitorum longus (disease-resistant), gastrocnemius (intermediate vulnerability), and tibialis anterior (vulnerable) muscles in mice revealed that disease susceptibility correlates strongly with a modified bioenergetic profile. Targeting of identified bioenergetic pathways by enhancing mitochondrial biogenesis rescued motor axon defects in SMA zebrafish. Moreover, targeting of a single bioenergetic protein, phosphoglycerate kinase 1 (Pgk1), was found to modulate motor neuron vulnerability in vivo. Knockdown of pgk1 alone was sufficient to partially mimic the SMA phenotype in wild-type zebrafish. Conversely, Pgk1 overexpression, or treatment with terazosin (an FDA-approved small molecule that binds and activates Pgk1), rescued motor axon phenotypes in SMA zebrafish. We conclude that global bioenergetics pathways can be therapeutically manipulated to ameliorate SMA motor neuron phenotypes in vivo.
Assuntos
Neurônios Motores/metabolismo , Atrofia Muscular Espinal/metabolismo , Fosfoglicerato Quinase/genética , Medula Espinal/metabolismo , Proteína 1 de Sobrevivência do Neurônio Motor/genética , Trifosfato de Adenosina/metabolismo , Animais , Axônios/metabolismo , Axônios/patologia , Modelos Animais de Doenças , Suscetibilidade a Doenças , Metabolismo Energético , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Camundongos , Mitocôndrias/metabolismo , Neurônios Motores/efeitos dos fármacos , Músculo Esquelético/metabolismo , Músculo Esquelético/patologia , Atrofia Muscular Espinal/genética , Atrofia Muscular Espinal/fisiopatologia , Fosfoglicerato Quinase/antagonistas & inibidores , Prazosina/administração & dosagem , Prazosina/análogos & derivados , Medula Espinal/crescimento & desenvolvimento , Medula Espinal/patologia , Proteína 1 de Sobrevivência do Neurônio Motor/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimentoRESUMO
Previously, we showed that the blockade of α1-adrenoreceptors in the median raphe nucleus (MnR) increased food intake in free-feeding rats, indicating that adrenergic mechanisms in the MnR participate in the regulation of food intake. However, the impact of such a pharmacological manipulation on other neural circuits related to food intake remains unknown. In the current study, we sought to identify forebrain regions which are responsive to α1-adrenergic receptor blockade and presumably involved in the modulation of the feeding response. For this purpose, we examined the induction of c-Fos immunoreactivity in forebrain structures following injections of the α1-adrenoceptor antagonist prazosin into the MnR of free-feeding rats. To determine the chemical identity of hypothalamic c-Fos-positive cells, we then conducted double-label immunohistochemistry for Fos/orexin (OX) or Fos/melanin-concentrating hormone (MCH). Finally, we combined anterograde tracing from the MnR with immunohistochemical detection of orexin. Prazosin injections into the MnR significantly increased food intake. The ingestive response was accompanied by an increase in Fos expression in the basolateral amygdala (BLA) and lateral hypothalamic area (LHA). In the LHA, Fos expression occurred in neurons expressing OX, but not MCH. Combined anterograde tracing experiments revealed that LHA OX neurons are prominently targeted by MnR axons. These findings suggest that intra-MnR injection of prazosin, via activation of orexinergic neurons in the LHA and non-orexinergic neurons in the BLA, evoked a motivational response toward food intake.
Assuntos
Antagonistas de Receptores Adrenérgicos alfa 1/administração & dosagem , Ingestão de Alimentos , Neurônios/metabolismo , Prazosina/administração & dosagem , Núcleos da Rafe/fisiologia , Receptores Adrenérgicos alfa 1/fisiologia , Animais , Complexo Nuclear Basolateral da Amígdala/metabolismo , Hormônios Hipotalâmicos/metabolismo , Hipotálamo/metabolismo , Masculino , Melaninas/metabolismo , Orexinas/metabolismo , Hormônios Hipofisários/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Núcleos da Rafe/efeitos dos fármacos , Ratos WistarRESUMO
Nowadays, it is assumed that therapeutic efficacy of antidepressants depends, at least partly, on their anti-inflammatory properties. The present study investigated for the first time the effect of 21-day oral administration of desipramine on the lipopolysaccharide (LPS)-stimulated IL-1ß concentration in the olfactory bulb, hypothalamus, frontal cortex, hippocampus and plasma of rats, and on the LPS-induced IL-1ß mRNA level in the olfactory bulb. Desipramine (15mg/kg/day) reduced significantly the LPS (250 µg/kg i.p.)-induced IL-1ß concentration in the olfactory bulb, hypothalamus and in plasma, and diminished the LPS effect on IL-1ß mRNA in the olfactory bulb. Plasma concentration of desipramine was comparable to its therapeutic range. By using the α1/α2-adrenoceptor antagonist prazosin and the unspecific ß-adrenoceptor antagonist propranolol given prior to LPS, we found that the effect of desipramine on LPS-induced IL-1ß production was partially mediated by both adrenoceptors in the olfactory bulb and plasma, and that ß-adrenoceptors contributed also to its effect on the stimulated IL-1ß concentration in the hypothalamus. The effect of LPS on the cerebral IL-1ß levels was, in part, mediated by ß-adrenoceptors and, in a region-specific manner, by α1/α2-adrenoceptors. The findings provide evidence for central and peripheral anti-inflammatory activity of desipramine and confirm the impact of the noradrenergic system on IL-1ß production induced by an immunostimulatory challenge.
Assuntos
Antidepressivos Tricíclicos/administração & dosagem , Encéfalo/efeitos dos fármacos , Desipramina/administração & dosagem , Interleucina-1beta/sangue , Interleucina-1beta/metabolismo , Lipopolissacarídeos/imunologia , Administração Oral , Animais , Antidepressivos Tricíclicos/sangue , Anti-Hipertensivos/administração & dosagem , Encéfalo/imunologia , Encéfalo/metabolismo , Desipramina/sangue , Esquema de Medicação , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Interleucina-1beta/biossíntese , Interleucina-1beta/genética , Bulbo Olfatório/efeitos dos fármacos , Bulbo Olfatório/metabolismo , Prazosina/administração & dosagem , Propranolol/administração & dosagem , RatosRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Hippadine is an alkaloid isolated from Crinum macowanii. Crinum macowanii is used in South Africa to treat oedema, 'heart disease', rheumatic fever, cancer and skin diseases, and belongs to the plant family Amaryllidaceae, assumed to have originated in the South African region. The aim of this study was to evaluate the effect of hippadine, an alkaloid extracted from Crinum macowanii, on the blood pressure (BP) and heart rate (HR) in anaesthetized male spontaneously hypertensive Wistar rats (SHR); and to find out if α1 and⧸or ß1 adrenoceptors contribute to its effects. MATERIALS AND METHODS: Hippadine (2.5-12.5mg/kg), adrenaline (0.05-0.20mg/kg), atenolol (0.5-40mg/kg) and prazosin hydrochloride (100-500µg/kg) were infused intravenously, and the BP and HR measured via a pressure transducer connecting the femoral artery and the PowerLab. Adrenaline increased the systolic, diastolic and mean arterial BP, while hippadine, atenolol and prazosin respectively decreased the systolic, diastolic and mean arterial BP. Increases in HR were observed with both adrenaline and prazosin, while reductions in HR were observed with atenolol and hippadine. Infusion of adrenaline in rats pre-treated with atenolol (30mg/kg), prazosin (400µg/kg), and hippadine (10mg/kg) led to similar increases in BP and HR in all groups. All changes in HR or BP were significant (p<0.05) and dose dependent. CONCLUSION: Hippadine decreases the BP and HR in SHR, and these effects may be due to α1 and ß1 adrenoceptor inhibition.
Assuntos
Alcaloides de Amaryllidaceae/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Crinum/química , Frequência Cardíaca/efeitos dos fármacos , Alcaloides de Amaryllidaceae/administração & dosagem , Alcaloides de Amaryllidaceae/isolamento & purificação , Animais , Anti-Hipertensivos/administração & dosagem , Anti-Hipertensivos/isolamento & purificação , Anti-Hipertensivos/farmacologia , Atenolol/administração & dosagem , Atenolol/farmacologia , Relação Dose-Resposta a Droga , Epinefrina/administração & dosagem , Epinefrina/farmacologia , Hipertensão/tratamento farmacológico , Masculino , Medicinas Tradicionais Africanas , Prazosina/administração & dosagem , Prazosina/farmacologia , Ratos , Ratos Endogâmicos SHR , Ratos Wistar , África do SulRESUMO
TUR of the prostatic gland for prostatic adenoma was made in 93 patients aged 54-81 years (mean age 64.4 +/- 7.5 years). The patients were divided into two groups. Patients of group 1 (n = 31) received no alpha-adrenoblockers, those of group 2 (n = 62) received terasosine in pre- and postoperative period. Group 2 patients demonstrated significant improvement in clinical parameters, postoperative hospital stay for them decreased by 11.3%, side effects were insignificant, their residual urine early after operation was 26.3 +/- 8.6 cm3 while 4 weeks after TUR it was 16.3 +/- 6.9 cm3. Thus, terasosine (setegis) can be recommended for use in early postoperative period after TUR of the prostate for prostatic adenoma as an effective and safe drug improving postoperative outcome.
Assuntos
Antagonistas Adrenérgicos alfa/uso terapêutico , Prazosina/análogos & derivados , Hiperplasia Prostática/tratamento farmacológico , Hiperplasia Prostática/cirurgia , Ressecção Transuretral da Próstata , Transtornos Urinários/tratamento farmacológico , Antagonistas Adrenérgicos alfa/administração & dosagem , Idoso , Idoso de 80 Anos ou mais , Esquema de Medicação , Humanos , Masculino , Pessoa de Meia-Idade , Período Pós-Operatório , Prazosina/administração & dosagem , Prazosina/uso terapêutico , Hiperplasia Prostática/complicações , Qualidade de Vida , Índice de Gravidade de Doença , Resultado do Tratamento , Transtornos Urinários/etiologiaRESUMO
The present study was undertaken to investigate the effect of an n-hexane extract of Myristica fragrans seeds on depression in mice by using the forced swim test (FST) and the tail suspension test (TST). M. fragrans extract (5, 10, and 20 mg/kg) was administered orally for 3 successive days to different groups of Swiss male young albino mice. M. fragrans extract significantly decreased immobility periods of mice in both the FST and the TST. The 10 mg/kg dose was found to be most potent, as indicated by the greatest decrease in the immobility period compared with the control. Furthermore, this dose of the extract was found to have comparable potency to imipramine (15 mg/kg i.p.) and fluoxetine (20 mg/kg i.p.). The extract did not have a significant effect on locomotor activity of mice. Prazosin (62.5 microg/kg i.p.; an alpha (1)-adrenoceptor antagonist), sulpiride (50 mg/kg i.p.; a selective D(2) receptor antagonist), and p-chlorophenylalanine (100 mg/kg i.p.; an inhibitor of serotonin synthesis) significantly attenuated the M. fragrans extract-induced antidepressant-like effect in the TST. Thus, extract of M. fragrans elicited a significant antidepressant-like effect in mice, when assessed in both the TST and the FST. The antidepressant-like effect of the extract seems to be mediated by interaction with the adrenergic, dopaminergic, and serotonergic systems.
Assuntos
Antidepressivos/administração & dosagem , Hexanos , Myristica/química , Extratos Vegetais/administração & dosagem , Sementes/química , Antagonistas Adrenérgicos alfa , Animais , Antagonistas de Dopamina , Interações Medicamentosas , Fenclonina/administração & dosagem , Fluoxetina/administração & dosagem , Imipramina/administração & dosagem , Masculino , Camundongos , Atividade Motora/efeitos dos fármacos , Prazosina/administração & dosagem , Antagonistas da Serotonina , Sulpirida/administração & dosagem , NataçãoRESUMO
The coitally induced gonadotropin-releasing hormone (GnRH)/luteinizing hormone (LH) surge in the rabbit is preceded by an enhanced secretion of hypothalamic norepinephrine (NE). To investigate if adrenergic receptors are essential for the GnRH/LH surge, we administered a specific alpha1 receptor blocker, prazosin, into either the arcuate nucleus-median eminence (AME) or the third cerebroventricle (3rd V) of tethered, freely moving intact female rabbits via push-pull perfusion (PPP). Dual cannulae for PPP and drug infusion were placed stereotaxically either into the AME or AME and 3rd V of each rabbit after insertion of a permanent femoral venous catheter for serial blood sampling. During an experiment, continuous PPP samples and 10-min intermittent blood samples were collected for 5-6 hr. Females received either prazosin or control medium (artificial cerebrospinal fluid into an AME or saline into a 3rd V cannula) for 4 hr, beginning 1 hr before coitus. Intraventricular infusion of prazosin significantly (P < 0.05) suppressed both the postcoital GnRH and the LH surges. Administration of prazosin into the AME also attenuated the magnitude of the postcoital GnRH surge (P < 0.05) whereas postcoital LH values were not decreased below that of the control group (P > 0.05). The results suggest that alpha1 receptors are physiologically active in the initiation of the postcoital GnRH release. These findings, along with our earlier report of enhanced postcoital NE secretion, reinforce the hypothesis that NE plays an essential role in the preovulatory GnRH/LH surge in rabbits.
Assuntos
Antagonistas Adrenérgicos alfa/farmacologia , Copulação/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Animais , Núcleo Arqueado do Hipotálamo/efeitos dos fármacos , Ventrículos Cerebrais/efeitos dos fármacos , Feminino , Hipotálamo/metabolismo , Hormônio Luteinizante/metabolismo , Eminência Mediana/efeitos dos fármacos , Norepinefrina/metabolismo , Prazosina/administração & dosagem , Prazosina/farmacologia , CoelhosRESUMO
This study investigated the parafascicular (PF) neuronal nociceptive responses and their modulation following electrical stimulation of the locus coeruleus (LC) and intrathecal (i.t.) or intracerebroventricular (i.c.v.) administration of two alpha-adrenoceptor antagonists, the alpha2-antagonist, yohimbine, and the alpha1-antagonist, prazosin. The main results were as follows: (1) the nociceptive evoked discharges in PF neurons were suppressed by preceding stimulation of LC; (2) the suppressive effect of LC stimulation on PF neurons was replaced by a facilitatory effect following pretreatment of i.t. yohimbine in 14 units tested, while i.t. prazosin failed to alter the LC-induced suppression, even when the prazosin dose was doubled; (3) i.c.v. pretreatment with prazosin strengthened the suppressive effect of LC stimulation on PF neurons; (4) i.c.v. norepinephrine (NE) administration induced, in PF neurons, a biphasic response to noxious stimulation; an early, brief (about 10 min) inhibitory effect followed by a late, long-lasting facilitatory effect; and (5) i.c.v. pretreatment of yohimbine or prazosin prevented the inhibitory or facilitatory responses released by NE, respectively. These results provide evidence that: (1) the LC-descending projections exhibit a suppressive effect on nociceptive transmission at the spinal level through alpha2-receptors; and (2) the LC-ascending projections exhibit dual effects, facilitatory and inhibitory, at the medial thalamus (PF) level through alpha1- and alpha2-receptors, respectively.
Assuntos
Locus Cerúleo/fisiologia , Nociceptores/fisiologia , Receptores Adrenérgicos/fisiologia , Tálamo/fisiologia , Agonistas alfa-Adrenérgicos/administração & dosagem , Agonistas alfa-Adrenérgicos/farmacologia , Antagonistas Adrenérgicos alfa/administração & dosagem , Antagonistas Adrenérgicos alfa/farmacologia , Animais , Feminino , Injeções Intraventriculares , Injeções Espinhais , Masculino , Norepinefrina/administração & dosagem , Norepinefrina/farmacologia , Prazosina/administração & dosagem , Prazosina/farmacologia , Ratos , Ratos Wistar , Receptores Adrenérgicos/administração & dosagem , Técnicas Estereotáxicas , Ioimbina/administração & dosagem , Ioimbina/farmacologiaAssuntos
Amilorida/administração & dosagem , Anti-Hipertensivos/administração & dosagem , Diuréticos/administração & dosagem , Hipertensão/tratamento farmacológico , Metildopa/administração & dosagem , Complicações Cardiovasculares na Gravidez/tratamento farmacológico , Resultado da Gravidez , Adulto , Combinação de Medicamentos , Quimioterapia Combinada , Feminino , Idade Gestacional , Humanos , Hidroclorotiazida/administração & dosagem , Hipertensão/diagnóstico , Tempo de Internação , Nifedipino/administração & dosagem , Prazosina/administração & dosagem , Gravidez , Complicações Cardiovasculares na Gravidez/diagnóstico , Resultado do TratamentoRESUMO
OBJECTIVE: To compare the long-term antihypertensive efficacy, tolerability, and metabolic effects of prazosin GITS and a sustained release (SR) preparation of nifedipine. DESIGN: Randomized, controlled, multicenter study of 26 weeks duration. SETTING: Office practices of 24 physicians in Chennai, Tamil Nadu, India. PATIENTS: Males and females, aged 30 to 70 yrs, with hypertension of JNC V stage 1 or 2 at the end of a 2-week placebo run-in period, and an abnormal lipid profile. Sufficient number of patients recruited so that at least 60 complete the entire study. INTERVENTIONS: Prazosin GITS (Minipress XL, 2.5-5 mg once daily) or sustained release nifedipine (Nicardia Retard 10-20 mg twice daily) for upto 6 weeks, continued upto 24 weeks in those showing a pre-defined response (SBP and/or DBP normalized, or DBP fall of at least 10 mm Hg with actual value of DBP < 95 mm Hg). Patients allocated to either of the two interventions by randomization. OUTCOME MEASURES: Percent patients showing pre-defined BP response at week 6; percent patients with DBP < 90 mm Hg, SBP < 140 mm Hg, and both; percent patients with DBP fall > or = 10 mm Hg; mean fall in BP among those receiving treatment for 24 weeks; mean change in blood glucose and serum lipids at the end of weeks 8, 16, and 24 of treatment; frequency and intensity of adverse events judged probably or definitely related to the drug. RESULTS: 54 patients randomized to prazosin GITS group and 52 to nifedipine SR group. Of these, 39 in prazosin GITS group (M 23, F 16; mean age-50. 6 yr, SEM 1.66) and 36 in nifedipine SR group (M 20, F 16; mean age-52.3 yr, SEM 1.71) completed the study. Percent patients with DBP < 90 mm Hg at 24 weeks: prazosin GITS--100%, nifedipine SR--100%; SBP < 140 mm Hg: prazosin GITS--94.9%, nifedipine SR--91.7%; both DBP < 90 mm Hg and SBP < 140 mm Hg: prazosin GITS--92.3%, nifedipine SR--91.7%; percent patients with DBP fall of 10 mm Hg or more at 24 weeks: prazosin GITS--76.9%, nifedipine SR--83.3%. The mean fall in the systolic and diastolic blood pressure from the end-of-placebo-phase values to all the other time points was comparable in the 2 groups. Treatment with prazosin GITS did not produce any statistically or clinically significant change in the metabolic parameters at the end of 24 weeks, while with nifedipine SR there was a significant increase in the serum LDL values at 24 weeks (p = 0.009). Adverse events probably or definitely related to the drug: prazosin GITS--1.9%, nifedipine SR--2.1%. CONCLUSION: Both drugs were equally effective and well tolerated. While prazosin GITS was neutral on serum lipids, use of nifedipine SR was associated with a significant increase in serum LDL cholesterol at the end of 24 weeks.
Assuntos
Anti-Hipertensivos/uso terapêutico , Hipertensão/tratamento farmacológico , Nifedipino/uso terapêutico , Prazosina/uso terapêutico , Adulto , Idoso , Anti-Hipertensivos/administração & dosagem , Preparações de Ação Retardada , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Metabolismo dos Lipídeos , Masculino , Pessoa de Meia-Idade , Nifedipino/administração & dosagem , Prazosina/administração & dosagemRESUMO
Se presentan dos casos de feocromocitoma. La sospecha se hace cuando presentan hipertensión arterial, sintomatología adrenérgica o hipotensión, el diagnóstico se realizó bajo sospecha clínica, bioquímicamente encontrando niveles de adrenalina y noradrenalina cuarenta y tres veces mayores a lo normal, la localización se realizó por ultrasonido, TAC, y rastreo con metayodobencilguanidina, los dos pacientes recibieron tratamiento médico a base de bloqueadores de canales de calcio, prazosín, Tratamiento definitivo resección quirúrgica, los dos pacientes actualmente se encuentran sanos sin tratamiento médico
Assuntos
Humanos , Masculino , Feminino , Adulto , Feocromocitoma/diagnóstico , Feocromocitoma/terapia , Ultrassom , Prazosina/administração & dosagem , Prazosina/uso terapêutico , Norepinefrina/administração & dosagem , Norepinefrina/uso terapêutico , Hipertensão/complicaçõesRESUMO
Our aim was to assess clinically whether there was any benefit in adding a single dose of sublingual nifedipine (a slow calcium channel blocker) to prazosin in the management of the cardiovascular manifestations of envenoming by the Indian red scorpion (Mesobuthus tamulus). A total of 163 patients stung by this species was admitted to hospital at Mahad between January 1991 and October 1993. Cardiovascular abnormalities were hypertension (59), of whom 42 had bradycardia and 17 had tachycardia; pulmonary oedema (14), of whom eight had hypertension and six hypotension; supraventricular tachycardia (eight), of whom three had hypotension and one died. Of the remaining patients, 78 demonstrated severe excruciating local pain at the site of sting but had no systemic involvement. Nineteen patients with hypertension and tachycardia were given a single dose of sublingual nifedipine plus prazosin on admission, then prazosin alone repeated 6 hourly. Five patients with massive life-threatening pulmonary oedema recovered after being given intravenous sodium nitroprusside. Prazosin alone helped to alleviate cardiovascular manifestations in the remaining 52 victims. One patient was admitted in a deep coma, 12 hr after the sting, and died. Eight victims whose blood pressure had been controlled in hospital by nifedipine plus prazosin developed acute pulmonary oedema necessitating additional doses of prazosin for recovery. Fifty-two victims treated with prazosin alone did not develop pulmonary oedema and the drug appeared to hasten the recovery. In the presence of high blood pressure, tachycardia, a murmur and impending myocardial failure, nifedipine appeared to contribute to cardiopulmonary instability and to augment myocardial oxygen consumption. In this situation calcium channel blockers should probably be avoided.
Assuntos
Doenças Cardiovasculares/tratamento farmacológico , Nifedipino/uso terapêutico , Prazosina/uso terapêutico , Picadas de Escorpião/tratamento farmacológico , Venenos de Escorpião/intoxicação , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Animais , Bradicardia/induzido quimicamente , Bradicardia/tratamento farmacológico , Doenças Cardiovasculares/induzido quimicamente , Criança , Pré-Escolar , Quimioterapia Combinada , Feminino , Coração/efeitos dos fármacos , Humanos , Hipertensão/induzido quimicamente , Hipertensão/tratamento farmacológico , Índia , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Nifedipino/administração & dosagem , Nifedipino/farmacologia , Nitroprussiato/uso terapêutico , Prazosina/administração & dosagem , Prazosina/farmacologia , Edema Pulmonar/induzido quimicamente , Edema Pulmonar/tratamento farmacológico , Picadas de Escorpião/complicações , Picadas de Escorpião/mortalidade , Escorpiões , Taquicardia/induzido quimicamente , Taquicardia/tratamento farmacológicoRESUMO
The antihypertensive efficacy of single-drug therapy with nifedipine (N), prazosin (P), or acebutolol (A) and the influence of these agents on coronary risk factors including hypoglycemia, hyperuricemia, and hyperlipidemia, were studied in adolescents with hypertension. Ninety patients (73 girls and 17 boys) aged 14 to 18 years with idiopathic hypertension (IH) were randomized into three groups. Each group received N, P, or A as single-drug therapy for six months. Systolic and diastolic blood pressures fell in all three groups, from 152/90 mmHg to 127/70 mmHg* with N, from 150/90 mmHg to 121/70 mmHg* with P, and from 148/92 mmHg to 122/74 mmHg* mmHg with A. In 17% of cases, N failed to reduce blood pressures below the 90th centiles. Heart rate was not influenced by N or P but decreased from 84 to 75 bpm with A. Although none of the drugs modified serum uric acid levels, fractional uric acid secretion rose with P and A (from 4.1% to 6% with P; and from 4.4% to 6% with A). The lipid profile remained unchanged under N and P, whereas a decrease in serum LDL-cholesterol from 99.6 to 88.8% mg* was seen with A. Fasting serum glucose levels increased from 86.4 to 92.7 mg %* in the group given A. N, P, and A are suitable for single-drug therapy of IH in adolescents; the most appropriate drug should be selected on the basis of medical history.
Assuntos
Acebutolol/uso terapêutico , Hipertensão/tratamento farmacológico , Nifedipino/uso terapêutico , Prazosina/uso terapêutico , Acebutolol/administração & dosagem , Acebutolol/farmacologia , Adolescente , Glicemia/análise , Glicemia/efeitos dos fármacos , Pressão Sanguínea/efeitos dos fármacos , LDL-Colesterol/sangue , LDL-Colesterol/efeitos dos fármacos , Protocolos Clínicos/normas , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Hipertensão/sangue , Hipertensão/fisiopatologia , Masculino , Nifedipino/administração & dosagem , Nifedipino/farmacologia , Prazosina/administração & dosagem , Prazosina/farmacologia , Ácido Úrico/sangueRESUMO
Pharmacodynamic and pharmacokinetic interactions have been reported when an alpha 1-antagonist is combined with a calcium antagonist. We evaluated the clinical usefulness of the combination of nifedipine (20 mg twice daily, b.i.d.) and doxazosin (2 mg once daily, o.d.) in hypertensive patients in whom blood pressure (BP) control was suboptimal after doxazosin (group A) or nifedipine (group B) as monotherapy and investigated the underlying kinetic and dynamic interactions, including changes in vascular responsiveness to i.v. infusions of angiotensin II (ANGII) and phenylephrine (PE). The combination was well tolerated and associated with further significant reductions in BP. After 4 weeks of combined therapy, average supine BP over 8 h was 122/77 in group A and 137/80 in group B as compared with 140/86 and 150/88 mm Hg, respectively, during monotherapy + placebo. The combination attenuated both phenylephrine and ANG-induced pressor responses: e.g., the mean PD15 values (dose of agonist required to increase systolic BP by 15 mm Hg) for group A at 1.5-3 h were 3.5 micrograms/kg/min for PE and 7.5 ng/kg/min for ANGII as compared with 2.9 and 2.3, respectively, during treatment with doxazosin and placebo. There was no evidence of a significant kinetic interaction between the two drugs and, in particular, addition of nifedipine had no effect on the steady-state kinetics of doxazosin. In conclusion, doxazosin and nifedipine are an effective antihypertensive combination in patients who require treatment with more than one drug.
Assuntos
Anti-Hipertensivos/uso terapêutico , Hipertensão/tratamento farmacológico , Nifedipino/uso terapêutico , Prazosina/análogos & derivados , Idoso , Análise de Variância , Angiotensina II/farmacologia , Pressão Sanguínea/efeitos dos fármacos , Doxazossina , Quimioterapia Combinada , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Pessoa de Meia-Idade , Nifedipino/administração & dosagem , Nifedipino/farmacocinética , Fenilefrina/farmacologia , Prazosina/administração & dosagem , Prazosina/farmacocinética , Prazosina/uso terapêuticoRESUMO
Prazosin is a highly selective alpha 1-adrenoceptor antagonist that decreases blood pressure by actions on both the peripheral and central (CNS) divisions of the nervous system. The present investigation was undertaken in an attempt to characterize the relative contribution of these two sympatholytic sites of action. Submaximal contractions of the nictitating membranes were evoked by electrical stimulation of the preganglionic cervical sympathetic nerve trunk and by stimulation of the posterior hypothalamus in anesthetized cats. In initial control experiments, phenoxybenzamine (0.1-3.0 mg/kg i.v.) produced an equivalent depression of evoked nictitating membrane responses from both peripheral and CNS sites of activation which suggests only a peripheral blocking action as well as functional equivalence of the intensity of CNS and peripheral nerve stimulation. In contrast, prazosin (3-300 micrograms/kg i.v.) caused a differential dose-related depression of the evoked responses with ED50s of 81.5 micrograms/kg (peripheral stimulation) and 12.5 micrograms/kg (CNS stimulation) respectively; P less than 0.05. Pretreatment with rauwolscine (500 micrograms/kg i.v.) totally prevented the differential CNS sympatho-inhibition produced by prazosin. These results indicate that, although both CNS and peripheral sites of drug action are manifest, the ED50 for prazosin-induced CNS sympatho-inhibition is approximately 6-fold less than that required for direct alpha 1-adrenoceptor blockade at the end organ. In addition, prazosin produces CNS sympatho-inhibition indirectly by means of an alpha 2-adrenoceptor mechanism.
Assuntos
Hipotálamo/metabolismo , Membrana Nictitante/efeitos dos fármacos , Nervos Periféricos/metabolismo , Prazosina/farmacologia , Anestesia , Animais , Gatos , Relação Dose-Resposta a Droga , Estimulação Elétrica , Feminino , Masculino , Prazosina/administração & dosagemRESUMO
The observations of a 16-week Tensiomin therapy of 10 hypertensive patients treated with hemodialysis have been discussed. The patients have been treated for about 5 years with hemodialysis, suffered from anuria and required besides systhematical ultrafiltration a combination antihypertensive therapy. Tensiomin was combined with Minipress, Trasicor, Depressan, Estulic and Corinfar by using three- or four-drug combinations. In the course of the administration of Tensiomin the doses of the other antihypertensive drugs could be decreased by 50% on average, while the blood pressure of the patients was normalized. By controlling the patients on weeks 1, 4, 12 and 16 of therapy toxic side-effects or notable pathological changes of the examined laboratory parameters (WBC, serum total protein, Na, K, Ca, P, bilirubin, blood sugar and SGOT values) were not seen. It has been concluded that Tensiomin is an effective drug in combination therapy applied for normalizing the hypertension of dialysed patients.
Assuntos
Captopril/uso terapêutico , Hipertensão/tratamento farmacológico , Diálise Renal/efeitos adversos , Adulto , Anti-Hipertensivos/administração & dosagem , Captopril/efeitos adversos , Quimioterapia Combinada , Feminino , Guanfacina , Guanidinas/administração & dosagem , Humanos , Hipertensão/etiologia , Masculino , Pessoa de Meia-Idade , Nifedipino/administração & dosagem , Oxprenolol/administração & dosagem , Fenilacetatos/administração & dosagem , Prazosina/administração & dosagemRESUMO
Urgent hypertension is defined by severe elevations of blood pressure without associated end-organ damage. The use of parenteral agents for this entity entails intensive monitoring and the potential for significant hemodynamic complications. Therefore, various oral regimens have been studied. Herein described are mechanisms of action, pharmacokinetics, clinical efficacy, and side effects of oral agents used in the treatment of urgent hypertension.