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1.
Resuscitation ; 49(3): 307-14, 2001 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-11723998

RESUMO

Eight subjects were placed in a decompression chamber for 31 days at pressures from sea level (SL) to 8848 m altitude equivalent. Whole blood lipid peroxidation (LP) was increased at 6000 m by a mean of 23% (P<0.05), at 8000 m by 79% (P<0.01) and at 8848 m by 94% (P<0.01). (All figures are means.) Two days after return to sea level (RSL), it remained high, by 81% (P<0.01), while corresponding erythrocyte GSH/GSSG ratios decreased by 31, 46, 49, 48%, respectively (each P<0.01). Erythrocyte SOD and plasma ascorbate did not change significantly. At sea level, maximal exercise induced a 49% increase in LP (P<0.01), and a 27% decrease in erythrocyte GSH/GSSG ratio relative to resting values (P<0.05). At 6000 m, the LP was enhanced further from 23 (P<0.05) to 66% (P<0.01), and after RSL from 81 (P<0.01) to 232% (P<0.01), while pre-exercise GSH/GSSG ratios did not change significantly. Exercise did not change plasma ascorbate relative to sea level or to 6000 m, but decreased after RSL by 32% (P<0.01). These findings suggest that oxidative stress is induced by prolonged hypobaric hypoxia, and is maintained by rapid return to sea level, similar to the post-hypoxic re-oxygenation process. It is increased by physical exercise.


Assuntos
Aclimatação/fisiologia , Altitude , Antioxidantes/metabolismo , Exercício Físico/fisiologia , Oxigenoterapia Hiperbárica , Estresse Oxidativo/fisiologia , Descanso/fisiologia , Adulto , Ácido Ascórbico/sangue , Ritmo Circadiano/fisiologia , Eritrócitos/metabolismo , França , Glutationa/sangue , Hematócrito , Humanos , Hipóxia/sangue , Peroxidação de Lipídeos/fisiologia , Masculino , Consumo de Oxigênio/fisiologia , Valores de Referência , Índice de Gravidade de Doença , Superóxido Dismutase/sangue , Substâncias Reativas com Ácido Tiobarbitúrico/metabolismo
2.
Aviat Space Environ Med ; 71(9): 929-34, 2000 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-11001347

RESUMO

BACKGROUND: Hyperbaric oxygen (HBO) increases monoamine deamination with related toxic products which aggravates hyperbaric oxygen (HBO) neurotoxicity. However, the possibility of some protective action of monoamines balanced by the toxicity of their metabolites have received little attention. HYPOTHESIS: To try to unmask this protective action, we compared brain monoamine levels in two strains of mice differing in HBO-sensitivity and their sensitivity to HBO after norepinephrine (NE) depletion by N-(2-chloroethyl)-N-ethyl-2-bromo benzylamine (DSP4). METHODS: Mice were exposed to 6 ATA O2 for 90 min (C57 strain) and 24 min (HBO-sensitive CD1 strain) so that 50% of mice of each strain had preconvulsive symptoms when decompressed and 50%), had one generalized convulsion. After microwave sacrifice, monoamines in the cerebral cortex, the striatum and the brainstem were analyzed. Another series studied the effect of DSP4 on the delay to symptoms of these HBO)-exposed mice. RESULTS: NE normoxic levels in the striatum were greater in the HBO-sensitive CD1 than in the C57 strain. Under HBO, NE levels in the striatum and the cortex of CD1 fell without any concomitant increase in its metabolite whereas in the C57 strain, NE decreased less and its metabolite increased. There was no strain difference and little change in the NE levels in the brainstem. The increase in toxicity induced by DSP4 was highly significant in both strains; moreover C57 strain was more affected than CD1. CONCLUSION: Monoamine depletion before HBO aggravates HBO neurotoxicity. As monoamine deamination is known to be toxic, this demonstrates that monoaminergic activation is protective. The greater toxicity of DSP4 in the C57 strain suggests the involvement of monoamines in the strain-differential susceptibility to HBO. The lower sensitivity of CD1 mice to DSP4 may be related to a combination of less NE activation under HBO that in C57 and greater activation of peroxidation and amino acids in CD1 sensitive strain.


Assuntos
Monoaminas Biogênicas/análise , Encéfalo/metabolismo , Oxigenoterapia Hiperbárica , Animais , Suscetibilidade a Doenças , Oxigenoterapia Hiperbárica/efeitos adversos , Peroxidação de Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Distribuição Aleatória
3.
J Neuroendocrinol ; 12(10): 970-6, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11012837

RESUMO

The effects of ionotropic excitatory amino acids agonists on the release of vasopressin from rat hypothalamic slices were studied. Incubation with increasing doses of NMDA, kainate or AMPA decreased the release of vasopressin in a dose-dependent manner. The values of the IC50 were 1.0, 9.6, or 3.7 x 10-8 M, respectively. The inhibitory effect of the various excitatory amino acids tested was blocked by coincubation with their respective antagonists. Vasopressin secretion was stimulated to 140.3 +/- 7.6% of controls when the slices were obtained from chronically (7 days) salt-loaded rats. Addition of 1 x 10-7 M NMDA or 1 x 10-6 M kainate to the incubation medium antagonized the salt loading-induced increase in vasopressin release. Incubation with 1 x 10-4 M tetrodotoxin did not change basal vasopressin release, but it blocked the decrease in vasopressin secretion induced by 1 x 10-7 M NMDA or 1 x 10-6 M kainate or 1 x 10-6 M AMPA. Incubation with 1 x 10-5 M phaclophen (a GABAB antagonist) and 1 x 10-5 M bicuculline (a GABAA antagonist) was without effect on basal vasopressin secretion while it reversed the inhibition of vasopressin release induced by 1 x 10-7 M NMDA. Incubation with 1 x 10-6 M GABA alone decreased vasopressin secretion to 64.6 +/- 6.9% of control values. The inhibitory effect of GABA did not change when 1 x 10-7 M NMDA was added to the incubation medium. These findings demonstrate that ionotropic excitatory amino acids agonists inhibit vasopressin secretion from hypothalamic slices. They strongly suggest that this inhibitory effect is mediated through local GABAergic interneurones.


Assuntos
Arginina Vasopressina/metabolismo , Agonistas de Aminoácidos Excitatórios/farmacologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Animais , Antagonistas GABAérgicos/farmacologia , Técnicas In Vitro , Masculino , Osmose , Cloreto de Potássio/farmacologia , Ratos , Ratos Sprague-Dawley , Transmissão Sináptica/efeitos dos fármacos , Transmissão Sináptica/fisiologia , Ácido gama-Aminobutírico/farmacologia
4.
Exp Physiol ; 82(4): 687-95, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9257111

RESUMO

The aim of this study was to investigate the effects of a high ambient pressure of He on vascular contraction induced by noradrenaline and to distinguish the effects of ambient pressure per se from those of increased pressure of inert gas. Rings of thoracic aorta were isolated from male Wistar rats. Isometric tension was measured in preparations exposed to 7.1 MPa (absolute pressure) of He. Dose-response curves for noradrenaline and contractions elicited by 120 mM KCl were compared with time-matched experiments performed at atmospheric pressure. The same protocol was also carried out under 7.1 MPa of N2. At the high pressure of He, the contraction elicited by noradrenaline was increased with no change in the response to K(+)-evoked depolarization. The tension developed in response to noradrenaline also increased under 7.1 MPa of N2 but the effects were less marked than during the He experiments. Moreover, the response to KCl was reduced in this circumstance. Hyperbaric conditions enhance the noradrenaline-induced contraction of rat aorta in vitro. This effect probably results from an action of pressure per se on activation of adrenoceptors. However, the hyperbaric-induced increase in vascular smooth muscle contraction is partially counteracted by high pressures of inert gases (N2, but also probably He), which impair the efficiency of the contractile machinery.


Assuntos
Agonistas alfa-Adrenérgicos/farmacologia , Músculo Liso Vascular/fisiologia , Norepinefrina/farmacologia , Animais , Aorta Torácica/fisiologia , Pressão Atmosférica , Hélio , Técnicas In Vitro , Masculino , Contração Muscular/fisiologia , Nitrogênio , Pressão , Ratos , Ratos Wistar
5.
J Neuroendocrinol ; 9(2): 93-7, 1997 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-9041361

RESUMO

It is known that in vivo excitatory amino acids (EAA) stimulate the hypothalamo-pituitary-adrenal axis. However their site of action is not fully understood. We investigated the possibility of a direct action of EAA on the secretion of the major adrenocorticotropin hormone (ACTH) secretagogue: corticotropin-releasing factor (CRF) from incubated rat hypothalamic slices. N-methyl-D-aspartic acid (NMDA) or L-glutamate (1 x 10(-7) to 1 x 10(-3) M) stimulated in a dose-dependent fashion CRF release. The maximal effect was obtained at a concentration of 1 x 10(-4) M for both drugs. The IC50 was 1.3 x 10(-5) M and 3.3 x 10(-5) M for NMDA and L-glutamate, respectively. Incubation with 2.5 x 10(-4) M D-2-amino-5-phosphonovalerate (a NMDA receptor antagonist) or 2-amino-4-phosphonobutyrate (a metabotropic receptor antagonist) was without significant effect on basal CRF secretion and completely blocked the increase in CRF release induced by 5 x 10(-5) M NMDA or L-glutamate, respectively. Incubation with 1 x 10(-4) M kainate or 0.5 x 10(-4) M AMPA did not change basal CRF secretion. Incubation with 2 x 10(-4) M gamma-D-glutamylglycine (a specific antagonist of kainate and AMPA receptor) had no effect under basal conditions or during exposure to kainate or AMPA. Our data demonstrate that EAA could stimulate directly CRF secretion, by an action through NMDA and metabotropic receptors, but not kainate or AMPA receptors. These findings may be relevant to the regulation of the hypothalamo-pituitary adrenal axis, both under basal conditions and during exposure to stress.


Assuntos
Hormônio Liberador da Corticotropina/metabolismo , Ácido Glutâmico/farmacologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , N-Metilaspartato/farmacologia , Animais , Técnicas de Cultura , Relação Dose-Resposta a Droga , Agonistas de Aminoácidos Excitatórios/farmacologia , Ácido Caínico/farmacologia , Masculino , Cloreto de Potássio/farmacologia , Ratos , Ratos Wistar , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia
6.
Peptides ; 18(7): 1039-43, 1997.
Artigo em Inglês | MEDLINE | ID: mdl-9357063

RESUMO

We studied the effect of various agonists of excitatory amino acid (EAA) receptor subtypes on somatostatin (SRIF) release from incubated rat hypothalamic slices. N-Methyl-D-aspartic acid (NMDA) and L-glutamate (1 x 10(-7) to 1 x 10(-3) M) stimulated, in a dose-dependent fashion, SRIF release. The maximal effect was obtained at a concentration of 1 x 10(-4) M for both drugs. The IC50 was 3.2 x 10(-5) M and 2.1 x 10(-5) M for NMDA and L-glutamate, respectively. Incubation with 2.5 x 10(-4) M D-2-amino-5-phosphonovalerate (a NMDA receptor antagonist) or 2-amino-4-phosphonobutyrate (a metabotropic receptor antagonist) was without significant effect on basal SRIF secretion and completely blocked the increase in SRIF release induced by 5 x 10(-5) M NMDA or L-glutamate, respectively. Incubation with 1 x 10(-4) M kainate or 0.5 x 10(-4) M alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) did not change basal SRIF secretion. Incubation with 2 x 10(-4) M gamma-D-glutamylglycine (a specific antagonist of kainate and AMPA receptors) had no effect under basal conditions or during exposure to kainate or AMPA. Our data demonstrate that EAAs stimulate SRIF secretion in vitro, by an action through NMDA and metabotropic receptors but not kainate or AMPA receptors.


Assuntos
Aminoácidos Excitatórios/farmacologia , Hipotálamo/efeitos dos fármacos , Hipotálamo/metabolismo , Somatostatina/metabolismo , Animais , Agonistas de Aminoácidos Excitatórios/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Ácido Glutâmico/farmacologia , Técnicas In Vitro , Ácido Caínico/farmacologia , Masculino , N-Metilaspartato/farmacologia , Cloreto de Potássio/farmacologia , Ratos , Ratos Wistar , Receptores de Glutamato/classificação , Receptores de Glutamato/efeitos dos fármacos , Ácido alfa-Amino-3-hidroxi-5-metil-4-isoxazol Propiônico/farmacologia
7.
Am J Respir Crit Care Med ; 153(1): 153-7, 1996 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-8542109

RESUMO

Substance P (SP), a neurotransmitter localized to primary sensory neurons, is found in the vagus nerve, nodose ganglion, sympathetic chain, and phrenic nerve in various animal species. However, the changes in endogeneous SP concentration under various circumstances that involve the participation of cardiorespiratory afferent nerves are still unexplored. In the present study, attention was focused on the variations in SP content measured by radioimmunoassay (RIA) in respiratory afferent nerves (vagus nerve, cervical sympathetic chain, phrenic nerve) and respiratory muscles (diaphragm, intercostal muscles) during positive inspiratory pressure (PIP) breathing alone or PIP with an expiratory threshold load (ETL) in rabbits. SP was found in all sampled structures in spontaneously breathing control animals, prevailing in the nodose ganglion. Left-versus right-sided differences were noticed in nerves. As compared with that in control animals, the SP concentration was markedly higher in vagal and sympathetic nervous structures during PIP or PIP with ETL, and also in the phrenic nerve during ETL breathing. The SP content did not vary in respiratory muscles. These observations suggest that two very common circumstances of mechanical ventilation are associated with an increased SP concentration in nervous structures participating in the control of breathing.


Assuntos
Gânglios Simpáticos/química , Nervo Frênico/química , Respiração com Pressão Positiva , Substância P/análise , Nervo Vago/química , Animais , Interpretação Estatística de Dados , Diafragma/química , Diafragma/fisiologia , Gânglios Simpáticos/fisiologia , Músculos Intercostais/química , Músculos Intercostais/fisiologia , Ventilação com Pressão Positiva Intermitente , Gânglio Nodoso/química , Nervo Frênico/fisiologia , Coelhos , Radioimunoensaio , Respiração/fisiologia , Nervo Vago/fisiologia
8.
Brain Res ; 676(2): 352-7, 1995 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-7614005

RESUMO

The contents of amino acids (AA) and ammonia (NH3) were measured in corpus striatum, brain stem and cerebral cortex of two strains of mice exposed to hyperbaric oxygen (HBO). Mice of the HBO-sensitive strain (CD1) were exposed to 600 kPa O2 for 24 min versus 90 min for mice of the normal C57 strain, so that 50% of the mice in both strains developed a generalized convulsion. In the cortex of exposed but unconvulsed (EXUN) C57 mice, the contents of taurine, glutamine and NH3 increased while that of GABA decreased when compared to control mice. In the CD1 mice, NH3 content was increased while that of Asp decreased. After a convulsion, NH3 was increased in both strains, the AA contents returned to normal in C57 but Asp remained low in CD1 mice. Somewhat similar changes occurred in the striatum except that NH3 levels were less affected while GABA ones were significantly decreased in the CD1 mice exposed to HBO, whether convulsed or not. In the EXUN brain stem, Asp and Glu contents decreased. These decreases were greater in C57 on a percentage basis than in CD1 mice. GABA content was decreased in the C57 strain. After a convulsion, Asp and Glu levels remained low and NH3 accumulated in CD1 whereas in C57 only the Glu level was decreased. The cortical and striatal changes may indicate a lesser GABA supply in C57 strain and some Asp release in CD1 strain. In the brain stem of both strains, Asp and Glu release is possible in addition to GABA in C57 strain.(ABSTRACT TRUNCATED AT 250 WORDS)


Assuntos
Aminoácidos/metabolismo , Amônia/metabolismo , Tronco Encefálico/metabolismo , Oxigenoterapia Hiperbárica/efeitos adversos , Convulsões/metabolismo , Telencéfalo/metabolismo , Análise de Variância , Animais , Gânglios da Base , Córtex Cerebral/metabolismo , Corpo Estriado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Convulsões/induzido quimicamente , Fatores de Tempo
9.
Life Sci ; 54(24): 1927-33, 1994.
Artigo em Inglês | MEDLINE | ID: mdl-8196510

RESUMO

In order to better understand the mechanisms underlying the reduction in GH secretion in diabetic rats, we have characterized and measured SRIH receptors in the hypothalamus and anterior pituitary gland 5 and 9 days after induction of diabetes in the rat. Experimental diabetes was induced by an intraperitoneal injection of streptozotocin (STZ) at a dose of 65 mg/kg. Basal plasma GH was significantly reduced in diabetic rats. Chronic insulin replacement therapy partly restored plasma GH and blood glucose levels in these animals. A significant reduction in SRIH receptor concentrations was demonstrated in the hypothalamus and anterior pituitary gland, 5- and 9- days after STZ injection. These changes were not significantly corrected by insulin replacement. Cerebral cortex SRIH receptor concentrations were unaffected by experimental diabetes. We conclude that hypothalamic and pituitary SRIH receptor levels are lowered in diabetic rats. These changes may contribute to aberrant GH secretion in diabetes and they indicate that pituitary sensitivity to exogenous somatostatin should be tested in diabetic patients.


Assuntos
Córtex Cerebral/química , Diabetes Mellitus Experimental/metabolismo , Hipotálamo/química , Adeno-Hipófise/química , Receptores de Somatostatina/análise , Animais , Hormônio do Crescimento/sangue , Masculino , Ratos , Ratos Sprague-Dawley
10.
Neurosci Lett ; 160(1): 1-3, 1993 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-8247319

RESUMO

In rat striatum, after one hyperbaric oxygen (HBO)-induced convulsion, polyamine changes are found that could promote N-methyl-D-aspartate (NMDA) activation. In the HBO-sensitive CD1 mouse, unlike in the common C57 strain, there is some support for NMDA activation after the HBO seizure. We measured PA cortical content before and after the first HBO-induced convulsion (about 608 kPa O2) in CD1 and C57 strains. Putrescine, spermidine and spermine were dansyl derived and analysed by HPLC. Exposure to HBO significantly increased putrescine content only in CD1 though a similar trend was observed in C57. No further increase was observed after convulsion whatever the strain. There were no significant changes in spermidine or spermine to support NMDA activation. Therefore, putrescine increase in CD1 cortex could reflect the free radical formation that is known to be greater in CD1 than in C57 mouse. Attempts to increase putrescine levels before HBO exposure hastened HBO-induced convulsion, less than spermidine or spermine. Because of physiological polyamine interconversion, additional experiments with indirect manipulation of putrescine levels and study of their time-course would precise these preliminary reports on putrescine and HBO.


Assuntos
Poliaminas Biogênicas/biossíntese , Córtex Cerebral/metabolismo , Oxigenoterapia Hiperbárica , Convulsões/metabolismo , Animais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Receptores de N-Metil-D-Aspartato/metabolismo , Convulsões/etiologia , Especificidade da Espécie
11.
Neuroendocrinology ; 55(5): 485-91, 1992 May.
Artigo em Inglês | MEDLINE | ID: mdl-1350065

RESUMO

In order to better understand the mechanisms underlying the reduction in growth hormone (GH) secretion in diabetic rats, we studied hypothalamic somatostatin secretion both in vivo (into hypophysial portal blood) and in vitro (from hypothalamic fragments) 5, 9 and 30 days after induction of diabetes. Experimental diabetes was induced by an intraperitoneal injection of streptozotocin (STZ) at a dose of 65 mg/kg. Basal plasma GH was significantly reduced in diabetic rats at all stages. Somatostatin levels in hypophysial portal blood was unaffected in 5-day STZ-diabetic rats and significantly increased 9 days after STZ administration. Chronic insulin replacement therapy in diabetic animals partly normalized somatostatin levels as well as plasma GH and glucose levels. A good correlation was observed between in vivo and in vitro experiments. Indeed, somatostatin release from hypothalamic fragments did not change 5 days after STZ-induced diabetes and significantly increased 9 and 30 days after STZ administration. The in vitro increase in hypothalamic somatostatin secretion was observed in 10 as well as in 33 mM glucose concentration in the incubation medium. In the same experiment, the in vitro hypothalamic corticotropin-releasing factor secretion was lowered 5 and 9 days after diabetes induction. We conclude that hypothalamic somatostatin release increases in diabetic rats. These changes may contribute to the reduction in GH secretion in these animals. However, since these changes occur after the onset of plasma GH decrease, a factor(s) other(s) than somatostatin may play a causal role in the reduction in GH secretion.


Assuntos
Diabetes Mellitus Experimental/fisiopatologia , Hipotálamo/metabolismo , Somatostatina/metabolismo , Animais , Hormônio Liberador da Corticotropina/metabolismo , Diabetes Mellitus Experimental/tratamento farmacológico , Hipotálamo Médio/metabolismo , Técnicas In Vitro , Insulina/uso terapêutico , Masculino , Ratos , Ratos Endogâmicos
13.
Acta Psychiatr Scand ; 81(1): 14-8, 1990 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-2330823

RESUMO

Plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) were found to be significantly higher in manic patients than in age- and sex-matched normal controls (n = 22). In 18 manic patients plasma MHPG correlated with manic symptoms but not with anxiety, depression, motor behaviour, acute psychosis, schizophrenia and severity of illness. A positive correlation between MHPG and grandiosity items on rating scales suggests a link with cognitive contents and therefore a relationship with central factors.


Assuntos
Transtorno Bipolar/sangue , Glicóis/sangue , Metoxi-Hidroxifenilglicol/sangue , Adolescente , Adulto , Cognição/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
14.
Peptides ; 10(5): 903-11, 1989.
Artigo em Inglês | MEDLINE | ID: mdl-2514417

RESUMO

We have compared the release of CRF induced by potassium depolarization, noradrenaline or dopamine as monitored either during superfusion of mediobasal hypothalamus or during incubation of whole hypothalamus. The superfusion device was improved in order to prevent gas leakage and to keep constant pO2 and pCO2 in the superfusion chamber. Basal CRF secretion as well as KCl- and norepinephrine-induced CRF release were comparable in superfusion and incubation experiments. Pharmacological investigations suggest that the stimulatory effect of norepinephrine on CRF release is mediated mainly through alpha 1 and alpha 2 adrenergic receptors, and partially through beta receptors.


Assuntos
Hormônio Liberador da Corticotropina/metabolismo , Dopamina/farmacologia , Hipotálamo/metabolismo , Norepinefrina/farmacologia , Perfusão/métodos , Potássio/farmacologia , Animais , Dióxido de Carbono/análise , Haloperidol/farmacologia , Hipotálamo/efeitos dos fármacos , Técnicas In Vitro , Masculino , Oxigênio/análise , Radioimunoensaio , Ratos , Ratos Endogâmicos
15.
Neuropsychobiology ; 20(2): 67-73, 1988.
Artigo em Inglês | MEDLINE | ID: mdl-3075724

RESUMO

Animal studies have suggested interspecies differences in brain norepinephrine (NE) metabolism, especially with regard to the relative proportions of 3,4-dihydroxyphenylethyleneglycol (DOPEG) compared to 3-methoxy-4-hydroxyphenylethyleneglycol (MOPEG). In order to question the value of both glycol metabolites as peripheral indices of central noradrenergic activity, a comparative study of plasma DOPEG and MOPEG (measured by HPLC) related to depression, sex, age and diagnostic categories (DSM-III) was carried out on depressed and control subjects. In addition, two groups of 8 patients were randomly submitted to a desipramine 150 mg/day, or a metapramine 450 mg/day antidepressant treatment influencing the formation of DOPEG and MOPEG in a different way. The study did not demonstrate any difference between DOPEG and MOPEG for most of the experimental factors. We found also a significant positive correlation between plasma levels of DOPEG and MOPEG. Our results support the idea that each of these two biological indices can be used in the assessment of central noradrenergic activity.


Assuntos
Encéfalo/metabolismo , Transtorno Depressivo/sangue , Glicóis/sangue , Metoxi-Hidroxifenilglicol/sangue , Norepinefrina/sangue , Adulto , Idoso , Idoso de 80 Anos ou mais , Antidepressivos Tricíclicos/uso terapêutico , Ensaios Clínicos como Assunto , Transtorno Depressivo/tratamento farmacológico , Desipramina/uso terapêutico , Dibenzazepinas/uso terapêutico , Feminino , Humanos , Masculino , Metoxi-Hidroxifenilglicol/análogos & derivados , Pessoa de Meia-Idade , Distribuição Aleatória
16.
Neurosci Lett ; 82(1): 65-70, 1987 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-2892159

RESUMO

During in vitro incubation of rat mediobasal hypothalamus (MBH), potassium and sodium gradients were high in the presence of glucose, pyruvate, lactate or the mixture glucose and pyruvate; in the absence of substrate, the ionic gradients were markedly lowered and corresponding somatostatin release from MBH was maximal. The specific effect of glucose on somatostatin release from MBH was tested under normal tissue polarization, i.e. in the presence of pyruvate. Under these more physiological conditions, somatostatin release was submaximal and inversely related to glucose concentrations (within the range 0-7 mM).


Assuntos
Glucose/farmacologia , Hipotálamo Médio/metabolismo , Potássio/farmacocinética , Sódio/farmacocinética , Somatostatina/metabolismo , Animais , Glucose/metabolismo , Técnicas In Vitro , Lactatos/farmacologia , Masculino , Potássio/farmacologia , Piruvatos/farmacologia , Ratos , Ratos Endogâmicos , Sódio/farmacologia
17.
C R Acad Sci III ; 305(9): 375-80, 1987.
Artigo em Francês | MEDLINE | ID: mdl-3113691

RESUMO

An experimental system allowing both the incubation and rapid transfert of rat hypothalamic slices has been developed in order to approach the regulation of CRF secretion. The release of CRF has been quantified by a specific radioimmunoassay. Under basal conditions, immunoreactive CRF release reached an optimum of 96.2 +/- 10.4 pg/3 hypothalami/20 min. A depolarizing concentration of KCl (56 mM) or veratridine (50 microM) applied for 20 min. induced a 222 and 257% increase, respectively, in CRF release. The in vitro CRF values released under basal and stimulated conditions are comparable to those of other hypothalamic neuropeptides. Furthermore, in vitro CRF release from the hypothalamus is in the same order of magnitude as in vivo CRF secretion estimated by hypophysial portal blood collection or median eminence push-pull cannulation.


Assuntos
Hormônio Liberador da Corticotropina/metabolismo , Hipotálamo/metabolismo , Animais , Hormônio Liberador da Corticotropina/análise , Hipotálamo/análise , Técnicas In Vitro , Masculino , Cloreto de Potássio/farmacologia , Protoveratrinas/farmacologia , Radioimunoensaio , Ratos , Ratos Endogâmicos
18.
Ann Endocrinol (Paris) ; 47(5): 342-9, 1986.
Artigo em Francês | MEDLINE | ID: mdl-2881511

RESUMO

GH secretory bursts are due to the combination of a pulsatile GRF release and a decreased Somatostatin secretion in hypophysial portal blood. In the intermediary periods, low plasma GH levels depend on the tonic release of hypothalamic Somatostatin. Experimental studies suggest that alterations in hypothalamic Somatostatin are involved in changes of GH secretion observed under physiological (foetal life, aging, stress), pharmacological (beta-blocking agents) and physiopathological conditions (starvation, obesity, diabetes). The Somatostatin analogue SMS 201-995 induces a long-lasting inhibition of GH secretion and may be useful in the treatment of acromegalic patients.


Assuntos
Hormônio do Crescimento/metabolismo , Hipotálamo/metabolismo , Hipófise/metabolismo , Somatostatina/fisiologia , Animais , Humanos , Somatostatina/uso terapêutico
20.
Chronobiol Int ; 1(1): 37-40, 1984.
Artigo em Inglês | MEDLINE | ID: mdl-6100993

RESUMO

Adenosine 3',5'-cyclic monophosphate (cAMP) was measured in whole brain of two inbred strains of mice (BALB/C and C57 BL/6) submitted to a lighting schedule consisting of 12 hr light (0700-1900) and 12 hr darkness (1900-0700). Different mean levels of cAMP were found in each strain. Furthermore, statistical analysis of diurnal brain cAMP fluctuations showed different nycthemeral rhythms in both strains. BALB/C was mainly characterized by the presence of very significant 0600 and 0800 harmonics and C57 BL/6 by an orthophase around 1700 hr. Because both strains were studied under the same experimental conditions of light, temperature and food availability, these factors cannot account for the observed differences, which were thus tentatively interpreted in terms of genetic regulatory processes.


Assuntos
Química Encefálica/efeitos da radiação , Ritmo Circadiano , AMP Cíclico/análise , Camundongos Endogâmicos BALB C/fisiologia , Camundongos Endogâmicos C57BL/fisiologia , Animais , Luz , Camundongos
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