Effect of chlorethylclonidine on arterial blood pressure and heart rate in the conscious rat

MT Piascik, MS Sparks and TA Pruitt

Department of Pharmacology, University of Kentucky, College of Medicine, Lexington.

The effect of chlorethylclonidine (CEC) on arterial blood pressure and heart rate (HR) has been evaluated in the conscious rat. CEC injection (25 mg/kg i.p.) caused a statistically significant decrease in mean arterial blood pressure (MAP) that was seen 24 hr after treatment. CEC also induced a decrease in HR that was maximal at 45 min but returned to pretreatment levels after 3 hr. CEC had no effect on the ability of isoproterenol to increase HR. CEC treatment had little effect on the pressor dose-response curve of either phenylephrine or BHT 920. When injected into the brain (25 mg/kg, lateral ventricle), CEC had no effect on MAP or HR. Yohimbine injected into the lateral ventricle had no effect on the response to i.p. CEC. Prazosin, used as a standard for comparison, caused a larger fall in MAP than CEC and this hypotension was associated with tachycardia and a marked shift (greater than 300- fold) in the phenylephrine pressor dose-response curve. A reactive analog of prazosin, SZL-49 [1-(4-amino-6,7-dimethoxy-2-quinazolinyl)-4- (2-bicyclo[2,2,2]octa- 2,5-diene-2-carbonyl)piperazine], had effects similar to prazosin on MAP and HR.(ABSTRACT TRUNCATED AT 250 WORDS)

Volume 262, Issue 3, pp. 901-906, 09/01/1992
Copyright © 1992 by American Society for Pharmacology and Experimental Therapeutics