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)

In previous reports, methamphetamine was shown to depress tyrosine hydroxylase (TH) activity in the rat corpus striatum. To evaluate further the mechanism of this decrease in TH activity, enzyme activity was measured in the rat corpus striatum and substantia nigra after repetitive and single-dose methamphetamine administration. Following repeated doses of methamphetamine, nigral TH activity decreased and reached 45% of controls at 12 hr and returned to normal at 60 hr. Striatal TH activity decreased to 40% of control at 36 hr and returned toward normal at 60 hr. When methamphetamine was administered every 6 hr for 30 hr and then discontinued, nigral TH activity returned toward control levels 4 days prior to recovery of striatal TH activity. Methamphetamine initially increased striatal dopamine levels at 6 hr (170% of control). Dopamine levels then decreased in parallel with striatal TH activity but failed to increase as the enzyme recovered. Concurrent administration of chlorpromazine with methamphetamine prevented the methamphetamine-induced decrease in nigral and striatal TH activity and striatal dopamine levels. The results indicate that the methamphetamine-induced depression of striatal and nigral TH activity may be related to increased stimulation of dopamine receptors in the striatum.
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PMID:Influence of methamphetamine on nigral and striatal tyrosine hydroxylase activity and on striatal dopamine levels. 0 86

Methamphetamine in large doses decreases striatal tyrosine hydroxylase activity. This effect is prevented by neuroleptic agents such as chlorpromazine and haloperidol which would suggest that released dopamine may be involved in the response. To test this hypothesis, we have altered dopamine synthesis with alpha-methyl-p-tyrosine and L-Dopa and found that dopamine synthesis is necessary for the observed depression of striatal TH activity by methamphetamine. In the adrenal gland, however, the increase in TH activity by methamphetamine is not prevented by inhibition of catecholamine synthesis. It is possible that released dopamine may be inhibiting TH activity by activation of pre- or postsynaptic dopamine receptors in the neostriatum resulting in activation of the neuronal feedback pathway or released dopamine may act on dendrodendritic autoreceptors in the substantia nigra.
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PMID:Influence of dopamine synthesis on methamphetamine-induced changes in striatal and adrenal tyrosine hydroxylase activity. 4 81

We reviewed records of adult patients admitted to our burn unit who were reported to abuse drugs or alcohol from 1985 to 1988. The proportion of patients reported as abusing drugs increased significantly from 1987 to 1988, compared to previous years. However, there was no increase in the proportion of patients reported to abuse alcohol. Patients identified as abusing drugs had longer hospital stays, compared to patients who were not reported to abuse substances. Methamphetamine and cocaine were the drugs most often abused by patients who abused drugs or both drugs and alcohol. Mechanisms of burn injury in these patients included "accidental" burn injury related to acute intoxication, and self-injury due to psychosis or depression.
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PMID:Drug and alcohol abuse in patients with acute burn injuries. 188 20

Methylamphetamine given intravenously as a single 15 mg dose led to a pronounced elevation of mood in 7 out of 21 depressed patients compared to a control injection of sterile water administered on another occasion in random order under double-blind conditions. All 7 responders experienced an increase of VAS self-ratings of hunger in contrast to what has been observed in normal subjects who show a decrease in hunger after amphetamine. The implications of these findings are discussed in the light of monoamine theories of depression and appetite control.
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PMID:The effects of methylamphetamine on mood and appetite in depressed patients: a placebo-controlled study. 357 40

A single injection of reserpine in an adult horse was believed to induce toxicosis for several days. Clinical signs included erratic, colic-like behavior followed by depression, bradycardia, miosis, ptosis, and paraphimosis. Diarrhea was not observed and may have been due to the effect of xylazine given with the reserpine. The horse was supported with IV fluids and intensive nursing care. Gradual improvement was noted 72 hours after the horse received the drug. Qualitative analysis via high-performance liquid chromatography was positive for reserpine. Methamphetamine is the recommended antidote but was not used in this case.
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PMID:Reserpine toxicosis in a horse. 399 54

Tyrosine hydroxylase (TH) levels in the rat neostriatum are decreased by chronic treatment with methamphetamine. GABAergic neurons could potentially interact with the nigrostriatal dopaminergic neurons in either the neostriatum or the substantia nigra; therefore, the GABA transaminase inhibitors, amino-oxyacetic acid, gamma-acetylenic GABA and ethanolamine-O-sulfate, were evaluated for possible influences on the methamphetamine-induced decrease in TH. TH was measured by the procedure of Nagatsu et al. (1964). Methamphetamine (10 mg/kg, s.c.) was given every 6 h for 24 h. Thirty-six h after initiation of the methamphetamine treatment, neostriatal TH activity was approximately 70% of control. Concurrent administration of amino-oxyacetic acid (20 mg/kg, i.p.) or gamma-acetylenic GABA (15 mg/kg, i.p.) with methamphetamine completely blocked the TH depression. Dose-response curves were constructed for amino-oxyacetic acid and gamma-acetylenic GABA. A single intraventricular injection of ethanolamine-O-sulfate (400 micrograms/rat), 2-6 h before initiating the methamphetamine regimen, also completely blocked the TH depression. These data suggest that the striatonigral or other GABAergic systems are involved in the regulation of the functional state of the nigrostriatal dopaminergic neurons, and that enhanced GABAergic function will antagonize the effects of high doses of methamphetamine.
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PMID:Blockade of methamphetamine-induced depression of tyrosine hydroxylase by GABA transaminase inhibitors. 610 24

In gross-behavioral observations, chlordiazepoxide, diazepam, meprobamate, and pentobarbital-Na produced excitatory behavior at 5 and 10, 1 and 2, 100 and 200, and 10 and 20 mg/kg p.o., respectively whereas afloqualone produced no excitatory behavior at doses up to 20 mg/kg p.o., these doses induce muscle relaxation and motor depression. Afloqualone depressed DRL response at 10 and 20 mg/kg p.o. Similar effects were seen with chlorpromazine (5, 10, 20 mg/kg p.o.). Chlordiazepoxide, meprobamate, and pentobarbital-Na facilitated DRL response at doses producing excitatory behavior. Methamphetamine (0.5, 1, 2 mg/kg p.o.) facilitated the response, dose-dependently. In CER, chlordiazepoxide (5, 10, 20 mg/kg p.o.), diazepam (1, 2, 5 mg/kg p.o.), and meprobamate (50, 100, 200 mg/kg p.o.) dose-dependently increased the response during the alarm period, regardless of the response during the safe period. Pentobarbital-Na (5, 10, 20 mg/kg p.o.) had much the same effect. Afloqualone slightly increased the response during the alarm period in one out of 3 rats at 5, 10, and 20 mg/kg p.o., respectively. Chlorpromazine and methamphetamine had no influence on the response during the alarm period at doses up to 20 and 2 mg/kg p.o., respectively. These results suggest that the pharmacological properties of afloqualone, as related to behavior differ from those of anti-anxiety drugs, hypnotics, and stimulants.
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PMID:[Effects of afloqualone, a new centrally acting muscle relaxant, on DRL response and CER in rats (author's transl)]. 612 Jan 27

Methamphetamine (MA) and ethanol (EtOH) are two commonly abused drugs. Previous behavioral studies indicated that MA may synergistically alter EtOH responses. In the present study, we found that local application of MA did not potentiate ethanol-induced depressions of the spontaneous activity of Purkinje neurons in urethane-anesthetized rats. We and others previously found that, in cerebellar Purkinje neurons, EtOH and gamma-amino-butyric acid (GABA)-mediated depressions can be enhanced by norepinephrine (NE) acting via beta-adrenergic receptors while these responses are decreased by activation of alpha-adrenergic receptors. In the present experiment, after blocking alpha-adrenergic receptors with prazocin, MA significantly enhanced EtOH responses in most of neurons studied. It has been reported that MA may directly and indirectly enhance alpha-adrenergic and beta-adrenergic receptor-mediated responses. The present study may suggest that MA can negatively modulate (antagonize) the depressant effects of ethanol via the alpha-adrenergic receptor, which oppose the positive modulatory mechanism (potentiation of EtOH depression) via actions of the beta-adrenergic receptors. We found that lesioning NE neurons with N-chloroethyl-N-ethyl-2-bromobenzylamine hydrochloride (DSP4), a selective noradrenergic neurotoxin, enhance the MA-facilitated ethanol responses, suggesting that this action of MA may not require NE. Since it has been reported that MA increases serotonin (5-HT) and catecholamine release from their nerve terminals, MA may potentiate EtOH depressions by facilitating the release of NE and 5-HT. Taken together, our data suggested that MA may modulate EtOH responses via catecholaminergic and serotonergic mechanisms in cerebellar Purkinje neurons.
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PMID:Methamphetamine facilitates ethanol-induced depressions in cerebellar Purkinje neurons of prazocin- or DSP4-treated rats. 861 6

Methamphetamine (METH) is a major drug of abuse which causes neurotoxicity by depleting dopamine, its metabolites, high-affinity dopamine uptake sites and tyrosine hydroxylase activity in the striatum. Dopamine depletion and reduced dopamine transit are associated with depression. S-Adenosylmethionine (SAM) is the chief methyl donor used in dopamine and other neurotransmitter metabolism in mammals. Low SAM is associated with depression and other psychological and neurological disorders in humans. SAM is used to treat depression and some other neurological and psychiatric disorders. The present study was designed to determine if single or multiple doses of METH induce alterations in blood or liver SAM in mice and if these correlate with dopamine levels in the striatum. Adult male C57 mice were injected intraperitoneally with either single (1 x 40 mg/kg) or multiple (4 x 10 mg/kg) doses of METH. Animals were sacrificed at various intervals. A single injection of METH resulted in slightly higher blood SAM levels at 4 hr. Multiple doses of METH resulted in decreased hepatic and blood SAM levels at 72 hr. Blood SAM returned to control levels by 1 wk. Published work shows that dopamine levels increase hours after a single injection of METH, whereas dopamine decreases days after multiple injections of METH. These present data clearly demonstrate that METH dosing leads to significant alterations in liver and blood SAM and that these changes in SAM levels correlate with changes in striatal dopamine levels.
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PMID:Methamphetamine treatment affects blood and liver S-adenosylmethionine (SAM) in mice. Correlation with dopamine depletion in the striatum. 966 77

Methamphetamine, called meth, crystal, or speed, is a central nervous system stimulant that can be injected, smoked, snorted, or ingested orally; prolonged use at high levels results in dependence. Methamphetamine (MA) is a derivative of amphetamine, which was widely prescribed in the 1950s and 1960s as a medication for depression and obesity, reaching a peak of 31 million prescriptions in the United States in 1967. Until the late 1980s, illicit use and manufacture of MA was endemic to California, but the MA user population has recently broadened in nature and in regional distribution, with increased use occurring in midwestern states. An estimated 4.7 million Americans (2.1% of the U.S. population) have tried MA at some time in their lives. Short- and long-term health effects of MA use include stroke, cardiac arrhythmia, stomach cramps, shaking, anxiety, insomnia, paranoia, hallucinations, and structural changes to the brain. Children of MA abusers are at risk of neglect and abuse, and the use of MA by pregnant women can cause growth retardation, premature birth, and developmental disorders in neonates and enduring cognitive deficits in children. MA-related deaths and admissions to hospital emergency rooms are increasing. Although inpatient hospitalization may be indicated to treat severe cases of long-term MA dependence, optimum treatment for MA abusers relies on an intensive outpatient setting with three to five visits per week of comprehensive counseling for at least the first three months. The burgeoning problems of increased MA use must be addressed by adequate treatment programs suitable for a variety of user types.
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PMID:History of the methamphetamine problem. 1090


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