Dichotomous cardiac and systemic vascular responses to cocaine in conscious rats.
This study examined the effects of cocaine on cardiac output in conscious freely-moving rats. Although pressor responses were similar at all doses, 14 of 32 rats had consistent declines in cardiac output (> 15%) and greater increases in systemic vascular resistance after administration of cocaine (5 mg/Kg, i.v.). Procaine (10 mg/Kg i.v.) did not mimic this effect in either subgroup. We propose that a subpopulation of rats exists with an enhanced susceptibility to cocaine-induced cardiac and systemic vascular alterations at higher doses.
Branch
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Department of Pathology, St. Louis University School of Medicine, Missouri 63104.
Knuepfer
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D000704:Analysis of Variance; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002302:Cardiac Output / Q000187:drug effects*; D002319:Cardiovascular System / Q000187:drug effects*; D003042:Cocaine / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D008297:Male; D011343:Procaine / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D014655:Vascular Resistance / Q000187:drug effects
D011343:Procaine; D003042:Cocaine