The tremorolytic action of beta-adrenoceptor blockers in essential, physiological and isoprenaline-induced tremor is mediated by beta-adrenoceptors located in a deep peripheral compartment.
The effects of intravenous propranolol 100 micrograms kg-1, sotalol 500 micrograms kg-1, timolol 7.8 micrograms kg-1, atenolol 125 micrograms kg-1 and placebo on essential, physiological and isoprenaline-induced tremor were studied. These beta-adrenoceptor blocker doses produced equal reduction of standing-induced tachycardia in essential tremor patients. Atenolol produced significantly less reduction of essential and isoprenaline-induced tremor than the non-selective drugs, confirming the importance of beta 2-adrenoceptor blockade in these effects. Propranolol and sotalol produced equal maximal inhibition of isoprenaline-induced tremor but propranolol was significantly more effective in reducing essential tremor. The rate of development of the tremorolytic effect was similar in essential, physiological and isoprenaline-induced tremors but all tremor responses developed significantly more slowly than the heart rate responses. It is proposed that these results indicate that the tremorolytic activity of beta-adrenoceptor blockers in essential, physiological and isoprenaline-induced tremor is exerted via the same beta 2-adrenoceptors located in a deep peripheral compartment which is thought to be in the muscle spindles.
Abila
B
B
Wilson
J F
JF
Marshall
R W
RW
Richens
A
A
D000319:Adrenergic beta-Antagonists / Q000494:pharmacology*; D000328:Adult; D000368:Aged; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D007545:Isoproterenol; D008297:Male; D008875:Middle Aged; D011943:Receptors, Adrenergic, beta / Q000187:drug effects*; D014202:Tremor / Q000139:chemically induced / Q000517:prevention & control*
D000319:Adrenergic beta-Antagonists; D011943:Receptors, Adrenergic, beta; D007545:Isoproterenol