PMID: 6108841Jan 1, 1980Paper

Effects of tiodazosin, praxosin, trimazosin and phentolamine on blood pressure, heart rate and on pre- and postsynaptic alpha-adrenergic receptors in the rat

Clinical and Experimental Hypertension : CHE
J P BuyniskiJ A Campbell

Abstract

Subcutaneous administration of tiodazosin (0.1-3 mg/kg), prazosin (0.01-1 mg/kg), trimazosin (10-30 mg/kg) and phentolamine (0.1-3 mg/kg) to conscious spontaneously hypertensive rats (SHR) produced graded decreases in blood pressure with the order of potency being prazosin > tiodazosin > phentolamine > trimazosin. Heart rate was elevated predominantly only by phentolamine and this was consistent with the activity of this agent for both pre- and postsynaptic alpha-adrenergic receptors. In contrast, tiodazosin, prazosin and trimazosin showed selectivity only for postsynaptic alpha-adrenergic receptors. Acute oral administration of tiodazosin and prazosin indicated tiodazosin to be about 1/2 as potent as prazosin. However, chronic administration of equivalent doses of the two compounds for 25 and 52 days via the drinking water indicated approxiately equivalent, sustained reductions in blood pressure. Furthermore, at the end of the 52-day chronic dosing period tiodazosin caused appreciably less alpha-adrenergic receptor antagonist activity than prazosin as assessed by the norepinephrine dose-pressor response profiles. These results indicate that following chronic dosing with tiodazosin in the rat other mechanisms besides alpha-adre...Continue Reading

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Citations

Sep 11, 1981·European Journal of Pharmacology·J W Constantine, H J Hess
Nov 10, 1987·European Journal of Pharmacology·D L DecktorM M Davis
Aug 1, 1986·Clinical and Experimental Pharmacology & Physiology·J VincentJ L Reid
Jan 15, 2014·Autonomic Neuroscience : Basic & Clinical·Elspeth M McLachlan, Ping Hu
Jan 1, 1986·Clinical and Experimental Hypertension. Part A, Theory and Practice·M NakaiY Matsui
Aug 1, 1983·Journal of Pharmacokinetics and Biopharmaceutics·P A MeredithJ L Reid
Jul 1, 1986·Biopharmaceutics & Drug Disposition·A W KelmanJ L Reid

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