Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Winter depressions in seasonal affective disorder (SAD) are associated with central serotonergic (5-HT) dysfunction. SAD patients demonstrate rather specific, state-dependent, abnormal increases in 'activation-euphoria' ratings following intravenous infusion of the 5-HT receptor agonist meta-chlorophenylpiperazine (m-CPP). Several studies are also consistent with abnormal serotonergic regulation of the hypothalamic-pituitary-adrenal (HPA) axis in SAD. Here, we investigated the effects of the 5-HT1A receptor partial agonist ipsapirone, which produces behavioral effects and HPA-axis activation, to further characterize the 5-HT receptor subtype-specificity of these disturbances in SAD. Eighteen SAD patients and 18 control subjects completed two drug challenges (ipsapirone 0.3 mg/kg and placebo) separated by 3-5 days in randomized order. We measured behavioral responses with the NIMH self-rating scale, and plasma ACTH, cortisol, and prolactin concentrations. Compared with placebo, ipsapirone was associated with significant increases in self-rated 'functional deficit' and 'altered self-reality', and in each of the hormones. There were no differences between groups on any measures. The level of depression in SAD patients was inversely correlated with their ipsapirone-induced cortisol responses. There were significant drug x order effects on baseline 'anxiety' scores, ACTH and cortisol concentrations, such that subjects were significantly more stressed (higher 'anxiety', ACTH and cortisol) prior to their first challenge compared with their second. In conclusion, post-synaptic 5-HT1A receptors appear to function normally in SAD. The previously observed m-CPP-induced behavioral abnormality may be mediated by either 5-HT2C or 5-HT7 receptors.
 ...
PMID:Serotonin hypothesis of winter depression: behavioral and neuroendocrine effects of the 5-HT(1A) receptor partial agonist ipsapirone in patients with seasonal affective disorder and healthy control subjects. 1035 79

Rats were given a single dose of reserpine (5 mg/kg s.c.) and behavioural responses to agonists at 5-HT receptor subtypes compared with those of control animals 21 days later. The following effects of activating postsynaptic 5-HT1A receptors by the agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) were significantly increased: tail-flick, reciprocal forepaw treading, flat body posture. The hyperphagic effect of activating presynaptic 5-HT1A receptors by 8-OH-DPAT tended to increase and hypothermia on activating postsynaptic 5-HT1A sites tended to decrease. The hyperlocomotor effect of activating 5-HT1A sites also tended to decrease possibly as a result of a dependence of this response on the known depletion of catecholamines by reserpine. Head shakes on activating 5-HT2A receptors by 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) and two effects of activating 5-HT2C receptors by 1-(3-chlorophenyl) piperazine (mCPP) were significantly increased (hypophagia, anxiety) and a third effect, hypolocomotion tended to increase but hypophagia on activating postsynaptic 5-HT1B receptors by CP-94, 253 was significantly attenuated. The results are discussed with particular reference to altered 5-HT function in depression.
 ...
PMID:Effect of reserpine on behavioural responses to agonists at 5-HT1A, 5-HT1B, 5-HT2A, and 5-HT2C receptor subtypes. 1046 92

Major depressive disorder (MDD) is a severe psychiatric disorder with a lifetime prevalence of about 15%.1 The importance of the genetic component is well accepted,2 but the mode of inheritance is complex and non-Mendelian. A line of evidence suggests the involvement of serotonin and dopamine neurotransmitters in the pathophysiology of depression. In the present study, 102 unipolar MDD patients and 172 healthy controls were genotyped for polymorphisms in four serotonergic and three dopaminergic candidate genes [tryptophan hydroxylase (TPH), serotonin receptor 2A (HTR2A), serotonin receptor 2C (HTR2C), serotonin transporter promoter region (5-HTTLPR), dopamine receptor D4 (DRD4), dopamine transporter (DAT1) and catechol-O-methyl transferase (COMT)]. There were no statistical differences between MDD patients and healthy controls in the genotypic and allelic distribution of all polymorphisms investigated. Thus, our study does not support a major role for these polymorphisms in contributing to susceptibility to MDD, although it does not preclude minor effects.
 ...
PMID:Association of unipolar major depressive disorder with genes of the serotonergic and dopaminergic pathways. 1048 58

The Fawn-Hooded (FH) rat strain, with well-documented changes in their serotonergic and noradrenergic systems, is a putative genetic model for some neuropsychiatric disorders like depression, alcohol abuse, and anxiety. Because social phobia frequently occurs in combination with these disorders and there are no social anxiety-related data in FH rats in the literature, we measured the behavior of FH rats in the social interaction test. In addition, the effects of the anxiogenic Serotonin-2C (5-HT2C) receptor agonist, m-chlorophenylpiperazine (m-CPP), were studied. Male FH, Wistar (W), and Sprague-Dawley (SD) rats were used in two different test conditions of the social interaction test: the high light, unfamiliar arena, associated with high anxiety, and the low light, familiar arena, associated with low anxiety-like behavior. All social behaviors were markedly diminished in FH rats that suggested higher anxiety in these animals. Total social interaction time was reduced by 60-70% in FH rats compared either to W or SD rats under high light, unfamiliar or low light, familiar conditions, respectively. Aggressive behavior was reduced at least by 85% in FH rats. Locomotor activity and exploratory behavior were only minimally, in most comparisons, not significantly affected in FH rats. Total social interaction time, aggression, and locomotor activity were decreased, and self-grooming increased by m-CPP (0.5 mg/kg, ip) in all three strains. m-CPP decreased total social interaction time thus, caused anxiety most efficiently in FH rats (reduced by 69%, 50%, and 55% in FH, W, and SD rats, respectively), but other effects of the drug were similar in the three strains. Our studies provide evidence that the FH rat strain may be a genetic model of social phobia or other anxiety disorders with impaired social behavior.
 ...
PMID:High social anxiety and low aggression in Fawn-Hooded rats. 1123 74

Disturbances of the serotonergic pathway have been implicated in many psychiatric disorders, including alcoholism, aggression, schizophrenia and depression. The personality dimension of harm avoidance is correlated positively with the activity of mesolimbic serotonergic neurons. The goal of this study was to determine the role of the genes in this pathway in the development of type II alcoholism. A sample of alcoholics and normal controls were screened with the variations in tryptophan hydroxylase (TPH), serotonin receptors (5-HT2A and 5-HT2C), serotonin transporter (5-HTT), and monoamine oxidase A (MAO-A) genes. The results of association studies for type II alcoholics were the most significant with 5-HTT (P = 0.011) and MAO-A (P = 0.029) genes. However, after correction for multiple comparisons, none of the results reached the significance level. These data indicate that the genes in the serotonergic pathway may be involved in the development of type II alcoholism but the gene effects are very small.
 ...
PMID:Serotonergic pathway genes and subtypes of alcoholism: association studies. 1152 23

5-HT research is now more than 50 years old, and it has generated a wealth of therapeutic agents, some of which have had a major impact on disease management. The 5-HT reuptake inhibitors (SSRIs) are among the most widely prescribed drugs for treating depression and a variety of other disorders including anxiety, social phobia and premenstrual dysphoria (PMD). The other major success stories of 5-HT research are the discovery of 5-HT1B/D receptor agonists for treating migraine and 5-HT3 receptor antagonists for chemotherapy and radiation-induced emesis. The role of 5-HT in the mechanism of action of antipsychotic agents remains a topic of intense research, which promises better treatments for schizophrenia in the future. Compounds interacting with 5-HT1F, 5-HT2C, 5-HT6 and 5-HT7 receptors are currently under investigation and may prove to have important therapeutic applications in the future.
 ...
PMID:The medical benefit of 5-HT research. 1188 47

Agomelatine (S 20098) has a unique and new pharmacological profile. It is a melatoninergic agonist and selective antagonist of 5-HT2C receptors, and has been shown to be active in several animal models of depression. The aim of this study was to determine the active dose of agomelatine in the treatment of major depressive disorder (DSM-IV criteria). The methodology used was a conventional double-blind design comparing three different doses of agomelatine (1, 5 and 25 mg once a day) with placebo over an 8-week treatment period. Paroxetine was used as the study validator. Seven hundred and eleven patients with a baseline mean score of 27.4 on the 17-item Hamilton Rating Scale for Depression (HAM-D) were included. On the pivotal analysis, the mean final HAM-D total score (Full Analysis Set LOCF) demonstrated agomelatine 25 mg to be statistically more effective than placebo. This was confirmed by other analyses and criteria (responders, remission, subpopulation of severely depressed patients, Montgomery-Asberg Depression Rating Scale, Clinical Global Impression-Severity of Illness). Agomelatine 25 mg alleviated the anxiety associated with depression, as measured on Hamilton Anxiety Scale. Paroxetine was found to be effective on pivotal analysis and most of the secondary criteria used to validate the study methodology and population. Agomelatine, whatever the dose, showed good acceptability with a side-effects profile close to that of placebo. In conclusion, this study demonstrates that agomelatine is efficient in the treatment of major depressive disorder and that 25 mg is the target dose.
 ...
PMID:Determination of the dose of agomelatine, a melatoninergic agonist and selective 5-HT(2C) antagonist, in the treatment of major depressive disorder: a placebo-controlled dose range study. 1217 86

Depression is an incapacitating disease which needs appropriate treatment. This article reviews the pharmacology of antidepressant drugs and the future perspectives of treating mood disorders such as depression. The foremost theory for explaining the biological basis of depression has been the monoamine hypothesis. Depression is due to a deficiency in one or other biogenic monoamines (serotonin, 5-HT; noradrenaline, NA; dopamine, DA). Antidepressant drugs are therefore classified according to their ability to improve monoaminergic transmission. Since this first theory, other explanations based on abnormal function of monoamine receptors or associated with impaired signalling pathways have been suggested. Notable progress has been accomplished in the treatment of major depressive disorders with new compounds recently discovered (selective serotonin reuptake inhibitors: SSRI; serotonin noradrenaline reuptake inhibitors: SNRI). Behavioural, electrophysiological and microdialysis studies have shown that serotonin (5-HT) receptors, mainly 5-HT1A, 5-HT1B and 5-HT2C sub-types, exert a key role in modulating antidepressant activity. Indirect activation of neurotransmitter receptors by antidepressants may also lead, via increases in endogenous levels of serotonin in synapses in specific brain regions, to activation of various G proteins coupled to a receptor, signal of transduction, transcription factors and neurotrophic factors such as brain-derived neurotrophic factor (BDNF). Thus, depression may be considered as a transduction mechanism anomaly. This hypothesis needs to be clarified by molecular biology. Although antidepressants have improved the therapeutic potential compared to tricyclics (TCA) in terms of reduced side effects, a number of problems still occur with these drugs. Clinical effects are not always observed until after this time has elapsed (4-6 weeks) and a substantial proportion of depressed patients show only partial or no response to antidepressants. Knowledge of the existence of links between neurotransmitter systems and the discovery of the most specific target, 5-HT receptors, should lead to improvements in antidepressant therapy. Developing drugs using innovative mechanisms such as directly acting on 5-HT receptors (5-HT1A agonists or 5-HT2 antagonists), would appear to be useful in the treatment of depression. The use of antidepressants in anxiety disorders such as obsessional compulsive disorders and even generalised anxiety, highlights the distinction between antidepressants and classic anxiolytics such as benzodiazepines, or even buspirone.
 ...
PMID:[Mechanism of action of antidepressants and therapeutic perspectives]. 1242 59

Dopamine neurons of the substantia nigra pars compacta receive a prominent serotonin (5-HT) projection from the dorsal raphe nucleus and important functional interactions between the serotonergic and the dopaminergic system have been postulated. In the present report we examined the role of 5-HT in the modulation of the metabotropic glutamate receptor-mediated inhibitory postsynaptic current (mGluR-IPSC) in midbrain dopamine neurons, and we found a reversible depression of this synaptic response at concentrations of 5-HT ranging from 100 nm to 30 microm (EC50 1.06 microm). This resulted in a shift towards excitation of the overall dopamine neuron response to glutamatergic synaptic input. This effect was not because of a direct modulation of the Ca2+-sensitive K+ conductances underlying the mGluR-IPSC, but was associated with a decrease in the intracellular calcium signal triggered by mGluR stimulation. Similar results were obtained with alpha-methyl-5-hydroxytryptamine and 5-methoxytryptamine, but not with 5-carboxamidotryptamine or 1-(3-chlorophenyl) piperazine. No significant depression of the mGluR-IPSC by 5-HT was observed in the presence of the 5-HT2 antagonist cinanserin or the 5-HT4 receptor antagonist RS 23597-190, whereas the 5-HT2C antagonist RS 102221 was ineffective. Our results demonstrate a powerful inhibition of the mGluR-IPSC by 5-HT in midbrain dopamine neurons, most probably through stimulation of 5-HT2A and 5-HT4 receptors.
 ...
PMID:Depression of mGluR-mediated IPSCs by 5-HT in dopamine neurons of the rat substantia nigra pars compacta. 1465 23

We have re-screened the genes for the 5-HT1A, 5-HT2A, 5-HT2C, and 5-HT7 serotonin receptors for genetic variants in a large African-American and Caucasian-American population sample. We have identified eight novel variants in these genes including four that are predicted to cause amino acid substitutions. These variants are additional candidates for association studies of behavioral disorders such as depression and schizophrenia as well as quantitative personality traits. We have also detected some, but not all, previously identified variants in these genes suggesting that many previously identified variants are unique to specific populations. The results of this study, and previous screens of serotonin receptors, demonstrate that the genes for serotonin receptors display marked population and molecular genetic complexity. These levels of complexity may have a substantial effect on genetic association studies of human behavioral variability related to these genes. We discuss the implications of these findings and propose methods to address complexity in genetic association studies.
 ...
PMID:Re-screening serotonin receptors for genetic variants identifies population and molecular genetic complexity. 1468 23


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>