Central beta-adrenoceptors can modulate 5-hydroxytryptamine-induced tremor in rats.
The effects of two beta 2-adrenoceptor agonists with different lipophilicities were studied on tremor induced by L-5-hydroxytryptophan (L-5-HTP) in pargyline- and carbidopa-pretreated rats. Tremor was recorded and analysed by an objective method based on accelerometry. Clenbuterol, a lipophilic beta 2-selective agonist, dose-dependently enhanced tremor intensity, whereas the hydrophilic beta 2-agonist terbutaline had no effect. The clenbuterol-induced enhancement of tremor was completely abolished by the beta 2-selective antagonist ICI 118,551 but unchanged by the beta 1-selective antagonist metoprolol. The results suggest that centrally located beta 2-adrenoceptors can mediate a modulation of 5-hydroxytryptamine-induced tremor in rats.
Hallberg
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D006916:5-Hydroxytryptophan / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000319:Adrenergic beta-Antagonists / Q000494:pharmacology; D000818:Animals; D002976:Clenbuterol / Q000037:antagonists & inhibitors / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011943:Receptors, Adrenergic, beta / Q000502:physiology*; D012701:Serotonin / Q000502:physiology*; D014202:Tremor / Q000139:chemically induced / Q000503:physiopathology*
D000318:Adrenergic beta-Agonists; D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D012701:Serotonin; D006916:5-Hydroxytryptophan; D002976:Clenbuterol