Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0026827 (hypotonia)
 5,860 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pharmacology and pharmacokinetics of clonidine and the symptoms and treatment of acute clinidine overdosage are reviewed. Clonidine, a relatively safe and effective antihypertensive agent when used at therapeutic dosages, reduces blood pressure through a centrally mediated reduction in vasomotor tone. The primary symptoms of clonidine overdosage are central nervous system depression, bradycardia, hypotension, miosis, hypotonia, respiratory depression and possibly seizures. Gastric lavage followed by administration of activated charcoal is used to decrease absorption following acute oral ingestion. Intravenous fluid therapy and dopamine infusion are recommended for severe hypotension, and atropine sulfate is used to manage persistent bradycardia. Treatment of hypotension with alpha-adrenergic blocking agents (e.g., tolazoline) is not recommended unless patients fail to respond to dopamine infusion and administration of i.v. fluids.
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PMID:Clonidine overdose: a review. 38 42

An all-night polygraphic study of sleep was carried out in 6 healthy volunteers acutely medicated with clonidine (225 micrograms), yohimbine (15 mg), a combination of both drugs or with placebo at random order under simple blind conditions. The conventional scoring of sleep stages was extended by an on-line analysis of the EEG according to Hjorth. Clonidine, an agonist at alpha2 receptors, induced increases of the stages 2 and 3 + 4 but a decrease of REM sleep; the reduction of the parameters mobility and complexity during non-REM sleep signified synchronization of the EEG. Yohimbine, an antagonist at the same receptor sites, enhancing noradrenaline release, increased stage 1 and REM sleep, but decreased the stages 2 and 3 + 4; increases of mobility during REM and non-REM sleep signified desynchronization. The combined treatment with clonidine + yohimbine reduced REM sleep, but not as extensively as clonidine alone; the Hjorth parameters were without significant alterations compared to placebo. The physiological hypotonia was enhanced by clonidine and the combined treatment with clonidine + yohimbine. These results favour the hypothesis of a noradrenergic facilitation of REM sleep.
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PMID:Effect of clonidine and yohimbine on sleep in man: polygraphic study and EEG analysis by normalized slope descriptors. 240 46

1. The effects of some alpha-adrenergic agonists and antagonists on electrically-evoked contractions and tension of chick expansor secundariorum muscle (ESM), and dependence of these events on extracellular calcium was investigated. 2. Both train and continuous electrical stimulation can produce regular contractions in preparations obtained from 40-60 day old chicks. 3. Clonidine had a biphasic action on the contractions produced by train electrical stimulation. In concentrations ranging from 10(-8) to 3 x 10(-7) M, clonidine decreased the contraction amplitude, but in higher concentrations, it caused an increase in both the muscle tension and the contraction amplitude. These effects were reversed by application of yohimbine although yohimbine by itself had no effect on the contractions. 4. Introduction of calcium free isotonic high potassium medium decreased muscle tone which was followed by further dose-dependent increase in tension, along with the addition of cumulative doses of CaCl2 (ED50 = 2.8 x 10(-3) M). 5. Nifedipine reduced the amplitude of ESM contractions produced by continuous electrical stimulation in a dose dependent manner (IC50 = 6.7 x 10(-7) M). 6. Methoxamine induced a completely dose dependent increase in muscle tension which was dependent on extracellular calcium and was inhibited by nifedipine. In the presence of 10(-8) M nifedipine, ED50 of methoxamine stimulatory effect increased from the control value of 2.2 x 10(-7) to 8.4 x 10(-7) M).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The role of calcium and alpha-adrenoceptors in contractile response of chick expansor secundariorum muscle to field stimulation. 751 4