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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Baseline cortisol levels at 8:00 a.m. and the cortisol responses at 90 and 120 min after oral administration of 200 mg 5-hydroxytryptophan (5-HTP) (L-isomer, non-enteric-coated) were assessed in 65 depressed inpatients. Patients were categorized according to DSM-III as major (296.22; 296.32; 296.23; 296.33; 296.24; 296.34) and minor (300.40; 309.00; 296.82) depressives. We observed a significant rise of plasma cortisol in patients with major depression at 90 (P = 0.0001) and 120 (P = 0.002) min, but not in patients with minor depression. Patients with major depression showed significantly higher cortisol responses than those with minor depression (P = 0.016). This significant rise of plasma cortisol after 5-HTP could be attributed to sex-linked differences: we observed significant (P = 0.0065) rises in cortisol responses in women with major depression compared to depressed men and women with minor depression. These differences could not be attributed to age, concomitant benzodiazepine use or pre/postmenopausal status. Baseline cortisol correlated negatively with the cortisol response to 5-HTP. The increased cortisol responses in women with major depression remained significant even after the effects of baseline cortisol were partialled out. This rise in cortisol response can be explained by an increased responsiveness of the hypothalamic-pituitary-adrenal axis to 5-HTP.
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PMID:The cortisol responses to 5-hydroxytryptophan, orally, in depressive inpatients. 295 97

In chronic experiments on dogs, a reverse correlation was revealed between the level of positive salivary conditioning and the amount of serotonin in the blood. Administration of 0.2 and 0.4 mg of serotonin into the anterior limbic cortex enhanced conditioning in animals with high initial amount of serotonin in the blood and decreased it in animals with low amount of serotonin in the blood. Subcutaneous administration of serotonin in doses 0.5, 1.0, 2.0 and 5.0 mg/kg augmented the small intestine electrical activity. Subcutaneous administration of the serotonin precursor 5-oxytryptophan (0.5 mg/kg) enhanced both the conditioning and the small intestine electrical activity. An increased level of serotonin in the blood was revealed in neuroses peculiar by a prolonged depression of conditioning.
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PMID:[Participation of serotoninergic mechanisms in the regulation of visceral functions during conditioned reflex activity]. 299 41

Fifty elderly patients (mean age, 68 years) affected by depression were treated with a combination (P3007) containing 3 mg of dihydroergocristine and 100 mg of levo-5-hydroxytryptophan or placebo for 60 days in a double-blind trial. Efficacy of treatment was evaluated by means of neuropsychic tests and rating scales for depression before treatment and after 30 and 60 days. Patients treated with the drug combination showed significant improvements in their depressive state and psychic performance, whereas no change was observed in patients receiving placebo. The treatment was well tolerated.
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PMID:Effects of a levo-5-hydroxytryptophan-dihydroergocristine combination on depression and neuropsychic performance: a double-blind placebo-controlled clinical trial in elderly patients. 311 2

Studies using the 5-hydroxytryptophan (5-HTP) animal model of depression have led to the development of the hypersensitive postsynaptic serotonin receptor theory of depression. To demonstrate more clearly that the 5-HTP-induced suppression is a centrally mediated phenomenon, rats were implanted with bilateral cannulae in the lateral hypothalamus and received microinjections of D,L-5-HTP (100-500 ng) 15 min after the start of a VI operant session (milk reinforcement). Significant decreases in responding were observed that were comparable to those obtained after a systemic injection of 50 mg/kg D,L-5-HTP. Rats receiving a microinjection of 5-HTP in the posterior hypothalamus did not exhibit a behavioral effect. Rats working on shock-avoidance schedules did not demonstrate response suppression following microinjection of 5-HTP into the lateral hypothalamus, which is the same result as that following systemic 5-HTP administration. These data support the important role previously assigned to central 5-HT mechanisms in the 5-HTP animal model of depression.
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PMID:Response suppression in rats after bilateral microinjection of 5-hydroxytryptophan in lateral hypothalamus. 325 38

Alterations in serotonin metabolism may be an important factor in the etiology and treatment of depression. In this regard, 5-hydroxytryptophan (5-HTP), a serotonin precursor, has been given to patients with depression. Although a review of these studies suggests that 5-HTP possesses antidepressant properties, additional trials are clearly indicated. Following a discussion of the pharmacology of 5-HTP, the authors highlight adverse effects associated with its administration to depressed patients, neurologic subjects, and normal individuals. Relatively few adverse effects are associated with its use in the treatment of depressed patients.
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PMID:5-Hydroxytryptophan: a review of its antidepressant efficacy and adverse effects. 329 25

A theory of excessive transmission of serotonin (5-HT) in depression has been previously proposed. The purpose of the present study was to test this theory further by using the model of depression in rats induced by L-5-hydroxytryptophan (5-HTP), the precursor of 5-HT. The drug effects on 5-HTP (25 mg/kg) induced behavioral depression were tested by chronic administration using methysergide which is a postsynaptic blocker of 5-HT, or by comparable clinical doses of antidepressant drugs. Methysergide (2 mg/kg) blocked 5-HTP induced depression on days 8 and 22 after initiation of medication by 70% and 83%, respectively. Among antidepressants, mianserin (2 mg/kg) was the first to produce an effect, displaying a 38% effect as early as 1 day after the start of medication and having blocking effects of 52% and 72% on days 8 and 22. Desipramine (5 mg/kg), doxepine (5 mg/kg), imipramine (5 mg/kg) and trazodone (10 mg/kg) showed no significant effect on days 1 and 8, and on day 22, 64, 36, 33 and 32% blocking, respectively. Amitriptyline had an initial effect of 41% at a dose of 10 mg/kg. Clomipramine (5 mg/kg), zimelidine (6 mg/kg) and chlorpromazine (2.5 mg/kg), which is a neuroleptic, showed no effect. Considering these results in light of recent data reported on the 5-HT synapse, it was suggested that 5-HTP induced depression may be induced by excessive transmission of 5-HT and that some antidepressant drugs may produce their effect by blocking this postsynaptic transmission. Based on these results, the mechanisms of human depression were discussed.
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PMID:Action of chronically administered antidepressants on the serotonergic postsynapse in a model of depression. 349 69

To determine the role of central serotonergic systems in modulating the cough reflex, the effects of serotonergic agonists on the respiration and the cough reflex were comparatively studied. Male and female cats were anesthetized with sodium pentobarbital. Respiration and cough reflex were measured using a pneumotachograph via a cannula inserted into the trachea. The cough reflex was elicited by electrical stimuli to the superior laryngeal nerve. Tranylcypromine, a MAO inhibitor, in a dose of 5 mg/kg, i.v., increased the respiration, but depressed the cough reflex. The serotonin precursor 5-hydroxytryptophan (5 mg/kg, i.v.) depressed the respiration and the cough reflex. Haloperidol (2 mg/kg, i.v.) abolished the tranylcypromine-stimulated respiratory responses, and it intensified the tranylcypromine induced cough depression. It is concluded that the increase in serotonin levels in the brain has a depressant influence on the central generating mechanisms of the cough reflex. Furthermore, central dopaminergic mechanisms seem to play a modulating role on the cough reflex.
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PMID:Involvement of central serotonergic mechanisms in the cough reflex. 349 20

Since reserpine precipitates depression in some hypertensive patients, we tested this drug on our animal model of depression. The present experiment was designed to measure the effects of chronic reserpine treatment on 5-hydroxytryptophan (5-HTP) induced behavioral depression in rats trained on a food reinforcement operant schedule. Based on the Aprison et al. model of depression involving the serotonergic system, we predicted the development of receptor supersensitivity of postsynaptic serotonin (5-HT) receptors due to the decreased release of this neurotransmitter as a consequence of chronic reserpine treatment. Rats were trained on a VI 1 reinforcement schedule and then divided into 3 chronic treatment groups. One received daily injections of a placebo, another 0.025 mg/kg reserpine and the third 0.05 mg/kg reserpine. We found that 5-HTP induced behavioral depression was potentiated in rats chronically treated with reserpine, thus suggesting the development of supersensitive 5-HT receptors. These results support the hypothesis that in some types of human depression a decreased release of 5-HT occurs of sufficient duration to permit the subsequent development of supersensitive 5-HT receptors.
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PMID:Potentiated 5-hydroxytryptophan induced response suppression in rats following chronic reserpine. 349 8

A number of properties common both for harman and its derivatives and for imipramine and pyrazidol were revealed: a capability to enhance impulse release of 3H-noradrenaline and 3H-serotonin from the rat brain slices, to reduce the duration of immobilization in mice swimming test, to increase at chronic administration to rats ED50 for clonidine (depression of the locomotor activity and orientation) and 5-hydroxytryptophan ("head twitch" phenomenon) and to decrease ED50 for propranolol (depression of orientation). The potential antidepressant activity of harman and its derivatives and their place among the conventional antidepressants are discussed.
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PMID:[Harman and its derivatives as potential atypical antidepressants]. 375 21

To test the hypothesis that a new potent and selective 5-HT2 receptor antagonist would be an excellent blocker of D,L-5-hydroxytryptophan (5-HTP)-induced response suppression in an animal model of depression, we administered LY53857 60 min prior to 5-HTP injections into rats working on an operant schedule for milk reinforcement. As predicted, LY53857 pretreatment significantly blocked 5-HTP depression (90%) in doses as low as 0.1 mg/kg ip. When the dose of LY58357 was further reduced to 0.025 mg/kg, blockade of 5-HTP-induced depression was still greater than 30%. In doses as high as 5.0 mg/kg, LY53857 alone had no effect on the baseline performance of rats working a VI 1 schedule. Pretreatment with desipramine (2.5 mg/kg), an antidepressant characterized as having major noradrenergic effects, did not significantly block the 5-HTP-induced depression. These data suggest that the 5-HTP-induced depression is mediated by serotonergic mechanisms involving 5-HT2 receptors, as LY53857 is a selective antagonist of these receptors. These data also support the suggestion, based on other published data from this laboratory, that some antidepressants are antagonizing 5-HT2 receptors in our animal model of depression and may also act in a similar manner in depressed patients. Thus, this new drug could be of interest as a possible antidepressant agent of the general type that was proposed earlier by Aprison and Hingtgen (1981).
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PMID:Blockade of a 5-hydroxytryptophan-induced animal model of depression with a potent and selective 5-HT2 receptor antagonist (LY53857). 387 59


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