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

We have investigated the developmental pattern of expression and activity of 17alpha-hydroxylase/C-17,20-lyase cytochrome P450 (cytochrome P450c17) in the liver, stomach, duodenum, and testis of rats from day 18 of pregnancy to adulthood. In the male liver, the enzyme became detectable at birth (135 pmol/mg protein x min) at a level comparable to that in the testis (188 pmol/mg protein x min). The activity then increased dramatically, reaching a peak at 8 days (691 pmol/mg protein x min), which was more than 4-fold the testicular levels in rats of the same age or in adults. Thereafter it declined steadily, becoming undetectable from puberty onward. The hepatic peak followed a depression in testicular activity (58 pmol/mg protein x min) on day 6. Northern and immunoblot analyses showed a good temporal correlation between enzyme activity and the occurrence of P450c17 messenger RNA (mRNA) and protein. The same patterns of mRNA and protein occurrence were observed in female rat liver, indicating that the hepatic CYP17 expression is not sexually dimorphic. Sequencing confirmed a complete identity in the coding region between hepatic and gonadal mRNAs. Hepatic P450c17 mRNA, however, was 150-200 bases longer than the gonadal counterparts. No significant expression of mRNAs encoding P450scc and P450arom was observed in liver of either sex at any age. In stomach and duodenum, enzyme activity was much lower (maxima at 25 and 14 pmol/mg protein x min, respectively) than that in liver, but persisted from the time of weaning onward. It is suggested that the hepatic peak in P450c17 activity may serve to convert circulating progestogens into androgens for gonadal aromatization during Sertoli and granulosa cell proliferation.
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PMID:Developmentally regulated expression and activity of 17alpha-hydroxylase/C-17,20-lyase cytochrome P450 in rat liver. 923 64

Effects of brain-derived neurotrophic factor (BDNF) in area CA3, the dentate gyrus, and medial entorhinal cortex were examined electrophysiologically by bath application of BDNF in slices containing the hippocampus and entorhinal cortex. Bath application of 25-100 ng/ml BDNF for 30-90 min increased responses to single afferent stimuli in selective pathways in the majority of slices. In area CA3, responses to mossy fiber stimulation increased in 73% of slices and entorhinal cortex responses to white matter stimulation increased in 64% of slices. After exposure to BDNF, these areas also demonstrated evidence of hyperexcitability, because responses to repetitive stimulation (1-Hz paired pulses for several s) produced multiple population spikes in response to mossy fiber stimulation in CA3 or multiple field potentials in response to white matter stimulation in the entorhinal cortex. Repetitive field potentials persisted after repetitive stimulation ended and usually were followed by spreading depression. Enhancement of responses to single stimuli and hyperexcitability were never evoked in untreated slices or after bath application of boiled BDNF or cytochrome C. The tyrosine kinase antagonist K252a (2 microM) blocked the effects of BDNF. In area CA3, both the potentiation of responses to single stimuli and hyperexcitability showed afferent specificity, because responses to mossy fiber stimulation were affected but responses to fimbria or Schaffer collateral stimulation were not. In addition, regional specificity was demonstrated in that the dentate gyrus was much less affected. The effects of BDNF in area CA3 were similar to those produced by bath application of low doses of kainic acid, which is thought to modulate glutamate release from mossy fiber terminals by a presynaptic action. These results suggest that BDNF has acute effects on excitability in different areas of the hippocampal-entorhinal circuit. These effects appear to be greatest in areas that are highly immunoreactive for BDNF, such as the mossy fibers and the entorhinal cortex. Although the present experiments do not elucidate mechanism(s) definitively, the afferent specificity, similarity to the effects of kainic acid, and block by K252a are consistent with previous hypotheses that BDNF affects acute excitability by a presynaptic action on trkB receptors that modulate excitatory amino acid transmission. However, we cannot rule out actions on inhibitory synapses or postsynaptic processes.
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PMID:Hyperexcitability in combined entorhinal/hippocampal slices of adult rat after exposure to brain-derived neurotrophic factor. 930 36

Experiments were conducted on mices to study the effect of strain MRe-600 Escherichia coli endotoxin, rifampicin, and their combination at the level of cytochrome p-450, b5, aminopyrine N-demethylase and aniline-r-hydroxylase activity in the liver, absorptive activity and oxygen dependent metabolism of macrophages, and free-radical processes in the liver. It was found that rifampicin removes the endotoxin-induced depression of microsomal oxidation in the liver, but potentiates the stimulating effect of the endotoxin on macrophageal absorptive activity and the "respiratory outburst" in these cells. The oxidative equilibrium in the liver in this case does not change.
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PMID:[Effect of rifampicin, endotoxin, and their combination on the phagocyte activity, microsomal oxidation, and free radical processes in the liver]. 946 May 95

One hundred sixty-six patients suffering from major depressive disorders were treated for 8 weeks with nefazodone in an open study in dosage ranges from 200 to 600 mg. This report focuses primarily on the first week of therapy and on the concomitant use of several benzodiazepines, one of which is not metabolized by the cytochrome system (temazepam). Triazolam response was further evaluated as a function of two nefazodone dosage regimens provided during the first week of therapy, one group receiving nefazodone 200 mg/day for 7 days, and another group receiving nefazodone 200 mg/day for 3 days, followed by 4 days with 400 mg/day. Finally, a comparison of three different nefazodone dosages, the third being 400 mg from day 1 on, was also carried out. Outcome measures included Hamilton Rating Scale for Depression total and the total of the three Hamilton Rating Scale for Depression insomnia items, as well as global improvement, a daily completed sleep questionnaire, and adverse event assessment. A combination of nefazodone with a benzodiazepine (BZ) caused more sedation than nefazodone alone; triazolam, the BZ with the shortest half-life and the highest dependence on the cytochrome 450 system for its metabolism, caused the least amount of sedation, and alprazolam and diazepam, the two daytime benzodiazepines, caused the most sedation. Triazolam caused significant and identical reduction of insomnia in both nefazodone groups. Compared with nefazodone 200 mg given as monotherapy, insomnia was significantly improved--not only by triazolam, but also alprazolam and diazepam, but not temazepam. The addition of nefazodone raised triazolam plasma levels to almost 500%, the plasma level of desmethyl-diazepam 87%, and that of alprazolam 34%. Temazepam plasma levels remained unchanged. When prescribing nefazodone with a benzodiazepine, one should expect an improved sleep pattern initially, but at the cost of clinically relevant daytime sedation. The prediction that temazepam, the only BZ not dependent on the cytochrome mechanism for metabolism, should be the least sedating, and triazolam, because of its cytochromic metabolism interference with nefazodone should be the most sedating, could not be confirmed. In fact, triazolam 0.25 mg capsules seem to be the safest treatment of choice when one has to combine a benzodiazepine with nefazodone in initial stages of therapy, at least of the four benzodiazepines tested in this study.
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PMID:Nefazodone in major depression: adjunctive benzodiazepine therapy and tolerability. 958 Mar 69

Children and adolescents with severe asthma frequently experience anxiety or depression with anxiety, which can undermine their response to treatment. In addition, these patients often receive theophylline and a variety of adrenergic stimulants, which can exacerbate or worsen anxiety. Such children occasionally are candidates for treatment with anxiolytic therapy. There is a paucity of drug disposition data in adolescents for benzodiazepines, the most frequently used antianxiety drugs. The authors monitored the steady state alprazolam plasma concentration in six children with severe asthma who were administered standard doses of alprazolam. In one patient administered concurrent therapy with troleandomycin, a recognized cytochrome 3A4 inhibitor, alprazolam plasma concentration was markedly elevated. Overall, the disposition data of alprazolam was consistent with data previously reported in adults. Alprazolam appeared to be safe and effective for use in adolescents with asthma.
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PMID:Therapeutic drug monitoring of alprazolam in adolescents with asthma. 963 21

1. Five drugs with the predominant pharmacologic effect of inhibiting the neuronal reuptake of serotonin are available worldwide for clinical use. This class of psychoactive drugs, known as selective serotonin reuptake inhibitors (SSRIs), is comprised of fluoxetine, sertraline, paroxetine, fluvoxamine, and citalopram. 2. The SSRIs appear to share similar pharmacodynamic properties which translate to efficacy in the treatment of depression and anxiety syndromes. The drugs are differentiated by their pharmacokinetic properties with regard to stereochemistry, metabolism, inhibition of cytochrome enzymes, and participation in drug-drug interactions. Studies focusing on the relationship of plasma drug concentration to therapeutic and adverse effects have not confirmed the value of plasma concentration monitoring. 3. This review summarizes the metabolism and relevant pharmacokinetic properties of the SSRIs.
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PMID:Metabolism and pharmacokinetics of selective serotonin reuptake inhibitors. 1037 20

Depression is a significant post-transplant complication often necessitating drug therapy. Many of the newer selective serotonin reuptake inhibitor (SSRI) antidepressants are metabolized by the same cytochrome P450IIIA isoenzyme system that is responsible for the metabolism of cyclosporine, and these agents pose an interactive risk in transplant patients. We have observed nearly a 10-fold increase in whole blood cyclosporine concentrations in a cardiac transplant patient shortly after the addition of nefazodone antidepressant therapy. We suggest there is a clinically significant drug-drug interaction between nefazodone and cyclosporine due to inhibition of cytochrome P-450 IIIA4 isoenzymes by nefazodone.
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PMID:Nefazodone and cyclosporine drug-drug interaction. 1052 54

Sex steroid hormones exert important influences on neuroendocrine and behavioural brain function. As neuroactive steroids they are able to modify neuronal excitability. Unbalanced synthesis may thus be implicated in pathophysiological conditions, such as epilepsy, migraine, depression and anxiety. In sex steroid metabolism, 17beta-hydroxisteroid dehydrogenases (17beta-HSDs) play a crucial role in catalyzing the final steps of androgen and estrogen biosynthesis. The hippocampus appears to be a major target area of neurosteroidal action. The expression of 17beta-HSD isozymes has not yet been studied in human hippocampus. Therefore, we investigated the expression of 17beta-HSD 1, 2, 3 and 4 mRNAs in hippocampal tissue specimens obtained at neurosurgery from 42 patients with pharmacoresistant temporal lobe epilepsy. A competitive RT-PCR assay was used to quantify the mRNA transcript level. 17beta-HSD 1 mRNA concentrations were 10000 fold lower in the hippocampus compared to placental tissue, whereas 17beta-HSD 3 mRNA concentrations were 50 fold lower than in testis and 17beta-HSD 4 concentrations were in the same order of magnitude as in liver. 17beta-HSD 2 mRNA was not expressed. 17beta-HSD 1, 3 and 4 mRNA concentrations in the hippocampus showed no significant differences between men and women and there were no significant differences in expression levels of these enzymes between patients with Ammon's horn sclerosis (AHS) and those with histopathologically normal hippocampus associated with extrahippocampal lesions. No significant correlation could be detected between duration of epilepsy, individual seizure frequency and expression levels of 17beta-HSDs. In conclusion, the present study is the first to demonstrate mRNA expression of 17beta-HSD 1, 3 and 4 in the epileptic human hippocampus. Together with data on 5alpha-reductase 1, 3alpha-hydroxisteroid oxidoreductase 2 and cytochrome P450scc, previously shown to be expressed in the human hippocampus also, our data provide further evidence for the existence of sex steroid formation and metabolism in this specific brain area.
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PMID:Expression of mRNAs encoding for 17beta-hydroxisteroid dehydrogenase isozymes 1, 2, 3 and 4 in epileptic human hippocampus. 1092 71

Ciprofloxacin, given to a patient successfully treated with methadone for more than 6 years, caused profound sedation, confusion, and respiratory depression. We suggest that this was caused by ciprofloxacin inhibition of CYP1A2 and CYP3A4 activity, two of the cytochrome p450 isozymes involved in the metabolism of methadone.
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PMID:Methadone, ciprofloxacin, and adverse drug reactions. 1114 98

Paroxetine is a potent and selective serotonin reuptake inhibitor (SSRI) with currently approved indications for the treatment of depression, obsessive-compulsive disorder, panic disorder and social phobia. It is also used in the treatment of generalized anxiety disorder, post traumatic stress disorder, premenstrual dysphoric disorder and chronic headache. Paroxetine, a phenylpiperidine derivative, is the most potent inhibitor of the reuptake of serotonin (5-hydroxytryptamine, 5-HT) of all the currently available antidepressants including the class of SSRIs. It is a very weak inhibitor of norepinephrine (NE) uptake but it is still more potent at this site than the other SSRIs. The selectivity of paroxetine, i.e., the ratio of inhibition of uptake of norepinephrine to serotonin (NE/5-HT) is amongst the highest of the SSRIs. Paroxetine has little affinity for catecholaminergic, dopaminergic or histaminergic systems and by comparison with tricyclic antidepressants (TCAs) has, therefore, a reduced propensity to cause central and autonomic side effects. Paroxetine exhibits some affinity for the muscarinic cholinergic receptor but much less than the TCAs. In addition, the adaptive changes of somatodendritic (5-HT(1A)) and terminal (5-HT(1B/1D)) autoreceptors observed with paroxetine are different to those observed with TCAs; it also inhibits nitric oxide synthase. It is both a substrate and an inhibitor of cytochrome isoenzyme P450 2D6. Paroxetine is well absorbed orally and undergoes extensive first pass metabolism that is partially saturable. Its metabolites are pharmacologically inactive in vivo. Steady state levels are achieved after 4-14 days and an elimination half-life of 21 h is consistent with once-daily dosing. There is wide inter-individual variation in the pharmacokinetics of paroxetine in adults as well as in the young and the elderly with higher plasma concentrations and slower elimination noted in the latter. Elimination is also reduced in severe renal and hepatic impairment. Serious adverse events are, however, extremely rare even in overdose. In summary, paroxetine is well tolerated and effective in the treatment of both depressive and anxiety disorders across the age range.
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PMID:Paroxetine: a review. 1142 May 71


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