Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023380 (lethargy)
 5,697 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many drugs differing widely in chemical structure uncouple mitochondrial oxidative phosphorylation in vitro. This observation has led to the hypothesis that in vivo uncoupling is the basis of their pharmacological activity. Serpasil, a parenteral preparation of reserpine, recently has been shown to uncouple oxidative phosphorylation in vervet monkey kidney mitochondria. Although the drug exhibits some properties of a "classical" uncoupler, our studies show that it has a dual effect on energy conservation. Reserpine released respiratory control in rat liver mitochondria only when dissolved in organic solvents (as in Serpasil) or when deprotonated. Reserpine also released the oligomycin-induced respiratory control in beef heart submitochondrial particles, and inhibited energized uptake of Ca2- by rat liver mitochondria. Reserpine had a dual effect on mitochondrial ATPase: It (a) enhanced ATP hydrolysis by intact liver mitochondria, and (b) inhibited ATP hydrolysis by submitochondrial particles of beef heart. On a molar basis, reserpine was less effective than carbonyl cyanide 3-chlorophenylhydrazone in all bioenergetic reactions examined. Homogenates and mitochondria isolated from brain and liver of rats stuporous from intraperitoneally injections of Serpasil exhibited no detectable abnormalities in respiratory states and responded to known uncouplers in the expected manner. There was no evidence of in vivo uncoupling of oxidative phosphorylation as a basis of the pharmacological activity of reserpine, although interference with energy transfer may be involved in toxic manifestations of the drug. The results indicate the need for caution in interpreting the action of drugs formulated in complex pharmaceutical preparations and based solely on in vitro experiments.
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PMID:Reserpine as an uncoupler of oxidative phosphorylation and the relevance to its psychoactive properties. 622 36

Reserpine in different doses was assigned in random, double-blind fashion to 329 patients with mild to moderate hypertension who had not achieved normotension with chlorthalidone therapy alone. The additional reduction of BP averaged 11.0/10.4 mm Hg with chlorthalidone, 50 mg, plus reserpine, 0.25 mg (C 50+R 0.25); 9.5/9.4 mm Hg with C 50+R 0.125; 6.4/8.5 mm Hg with C 50+R 0.05; and 9.9/9.6 mm Hg with C 25+R 0.125. The percentage of patients in whom control was achieved at diastolic BP less than 90 mm Hg and at least 5 mm Hg below baseline with either chorthalidone alone or with reserpine added was 65% with C 50+R 0.25, 69% with C 50+R 0.125, 58% with C 50+R 0.05, and 56% with C 25+R 0.125. Side effects of lethargy and impotence noted by patients with the 0.05-mg dose of reserpine were only one third of those noted with the 0.25-mg dose, although the incidence of other side effects did not differ. These results indicate that hypertension in many persons can be controlled by less than customary doses of reserpine in combination with a diuretic.
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PMID:Low doses v standard dose of reserpine. A randomized, double-blind, multiclinic trial in patients taking chlorthalidone. 675 48

Traditional centrally acting antihypertensives have been associated with a high incidence of adverse effects and are no longer recommended as first-line therapy. The newer imidazoline receptor agonists must overcome this reputation if they are to gain recognition as potential first-line agents for hypertension. Methyldopa, a centrally acting alpha(2)-agonist, is characterized by a number of serious adverse reactions that limit its use. Although unpredictable idiosyncratic or hypersensitivity reactions are uncommon, these include hepatitis, myocarditis, and hemolytic anaemia. Less serious problems such as abnormal liver function tests, positive Coombs test, drug-induced fever, and pancreatitis also occur. Central side effects include drowsiness, fatigue, lethargy, sedation, depression, psychotic reactions, nasal stuffiness, impotence, and exacerbation of Parkinsonism. In hypertensive men, methyldopa is less well tolerated than either captopril or propranolol, and up to 20% of patients discontinue therapy because of adverse effects. Clonidine acts primarily as an alpha(2)-agonist but also acts as an agonist at imidazoline receptors in the rostroventrolateral medulla. It is equipotent to most other antihypertensives but is considerably less well-tolerated in comparative trials. The principal adverse effects of clonidine are drowsiness, sedation, lethargy and dry mouth. Reserpine acts primarily by depleting central catecholamine neurotransmitter stores. It was very extensively used in early hypertension trials, but its central side effects of sedation, nasal stuffiness, and severe depression are now considered so undesirable that the drug is seldom prescribed. The imidazoline (I1) agonists moxonidine and rilmenidine act selectively and have very little central alpha(2)-agonist activity. In comparative studies against placebo and other reference antihypertensives, the only adverse effect consistently associated with these drugs was dry mouth (approximate placebo-corrected incidence 10%). Sedation was not pronounced. Withdrawal syndromes are complex pathophysiologic processes and occur with a variety of antihypertensive drugs. Cessation of therapy with clonidine and, to a lesser extent, methyldopa may result in a severe withdrawal syndrome characterized by restlessness, sweating, anxiety, tremor, palpitations, and headache. There may be a rapid rise in blood pressure, often with a true "rebound" to higher than pretreatment levels. Plasma and urinary catecholamine levels are increased, and fatalities have been reported. It is important to stress that such a syndrome has not been recorded, in animal or human studies, with either moxonidine or rilmenidine.
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PMID:Aspects of tolerability of centrally acting antihypertensive drugs. 887 99

The venom of the parasitoid wasp Ampulex compressa induces long-lasting hypokinesia in the cockroach prey. Previous work indicates that the venom acts in the subesophageal ganglion to indirectly affect modulation of thoracic circuits for locomotion. However, the target of the venom in the subesophageal ganglion, and the mechanism by which the venom achieves its effects are as yet unknown. While the stung cockroaches appear generally lethargic, not all behaviors were affected, indicating that the venom targets specific motor systems and not behavior in general. Stung cockroaches were observed "freezing" in abnormal positions. Reserpine, which depletes monoamines, mimics the behavioral effects of the venom. We treated cockroaches with antagonists to dopamine and octopamine receptors, and found that the dopamine system is required for normal escape response. Dopamine injection induces prolonged grooming in normal cockroaches, but not in stung, suggesting that the venom is affecting dopamine receptors, or targets downstream of these receptors, in the subesophageal ganglion. This dopamine blocking effect fades slowly over the course of several weeks, similar to the time course of recovery from hypokinesia. The similarity in the time courses suggests that the mechanism underlying the hypokinesia may be the block of the dopamine receptors.
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PMID:Are monoaminergic systems involved in the lethargy induced by a parasitoid wasp in the cockroach prey? 1201 2