Cardiovascular effects of methamphetamine in dogs treated chronically with the amine.
Methamphetamine is one of a group of sympathomimetic amines that lower blood pressure upon chronic administration to hypertensive dogs. To determine whether tolerance to the cardiovascular effects of these drugs could play a role in their antihypertensive action, acute blood pressure responses to oral d-methamphetamine were determined in trained conscious renal hypertensive dogs at weekly intervals during treatment with the drug for 2 months. Responses were also obtained in similarly treated normotensive dogs and in normotensive and hypertensive animals receiving l-methamphetamine. Pressor responses to d-methamphetamine in hypertensive dogs remained unchanged throughout treatment, while in all other cases they diminished gradually. Only the dextro isomer reduced blood pressure chronically in the hypertensive group. It was concluded that tolerance is not involved in the antihypertensive effect of methamphetamine and that, considering the stereo specificity of this effect, residual lowering of blood pressure might involve formation of a false mediator metabolite of the amine.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D004285:Dogs; D004361:Drug Tolerance; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D013237:Stereoisomerism
D008694:Methamphetamine