Intravenous (+)-methamphetamine causes complex dose-dependent physiologic changes in awake rats.
Hemodynamic and temperature dose-response relationships were characterized in freely moving rats following i.v. (+)-methamphetamine administration to mimic the rapid onset of effects experienced by many human users. Rats received saline and (+)-methamphetamine in a repeated-measures, mixed-sequence design at 22+/-1 degrees C. Significantly greater blood pressure and heart rate elevations were observed after 1.0 and 3.0 mg/kg (+)-methamphetamine vs. 0.1 and 0.3 mg/kg. The time to peak hemodynamic values and the duration of effects were significantly greater after 3.0 mg/kg vs. the lower doses. The time to peak temperatures was significantly longer after 1.0 mg/kg vs. the lower doses. Following 3.0 mg/kg, all rats experienced temperature decreases before having elevated temperatures. The duration and magnitude of the delayed temperature elevations were significantly greater after 3.0 mg/kg vs. the lower doses. In conclusion, the (+)-methamphetamine-induced hemodynamic and temperature effects were not temporally synchronized, and the complex responses were not linearly related to dose.
Arora
H
H
Department of Anesthesiology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR 72205, USA.
Owens
S M
SM
Gentry
W B
WB
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D001831:Body Temperature / Q000187:drug effects*; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D003971:Diastole; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics / Q000187:drug effects*; D007275:Injections, Intravenous; D008297:Male; D008694:Methamphetamine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013599:Systole; D013997:Time Factors; D014851:Wakefulness
D000697:Central Nervous System Stimulants; D008694:Methamphetamine