Effect of Clonidine on Blood Pressure, Heart Rate and Body Temperature in Conscious Rats

Abstract

Abstract-Effects of clonidine on blood pressure, heart rate and rectal temperature in conscious rats were examined. Clonidine (0.1-1 mg/kg s.c.) caused a prevailing pressor response and dose-dependently a fall in heart rate and body temperature.The pressor response to clonidine (0.3 mg/kg s.c.) was completely reduced by phentolamine (10 mg/kg s.c.), chlorpromazine (10 mg/kg s.c.) but not by hexamethonium (30 mg/kg i.p.), guanethidine (30 mg/kg s.c.) or reserpine (5 mg/kg s.c. 18 hr+ 1 mg/kg i.p. 4 hr prior to clonidine). Conversely, a remarkable potentiation of the pressor response to clonidine was observed after treatment with reserpine. The bradycardia with clonidine (0.3 mg/kg s.c.) was significantly reduced by phentolamine, chlorpromazine or atropine (5 mg/kg s.c.) but was potentiated by reserpine. The hypothermia with clonidine (0.3 mg/kg s.c.) was not influenced by phentolamine or atropine but was significantly potentiated by chlorpromazine.From the above results it is suggested that the pre vailing pressor response to clonidine in conscious rats is due to a stimulation of peri pheral a-adrenoceptors, the bradycardia with clonidine is exerted through the sympa thetic pathway and the baroceptor-vagal reflex, and that the hypothermia with clonidine is mainly due to the central mechanism.

The locus coeruleus contributes to the anorectic, nausea, and autonomic physiological effects of glucagon-like peptide-1

“…2E). While clonidine, administered at a dose known to alter HR and body temperature (40), induced activation of LC NE neurons increased pupil dilation, as previously reported (41), LC Ex-4 had no effect on pupil to iris ratio (Fig. 2F).…”

Effects of Clonidine on the Cardiovascular, Renal, and Inflammatory Responses to Experimental Bacteremia

“…Other effects of clonidine were a decrease in body temperature, which has been shown to be due to a central action on a 2adrenoceptors (34,35). Clonidine given as a high bolus dose has been shown to cause respiratory depression and severe hypoxemia in sheep (36), but this effect was not seen with infusion of clonidine in septic sheep.…”

Clonidine and a ?-agonists induce hyperthermia in rats at high ambient temperature

“…For instance, while NA or the a2-agonist clonidine (CLON) lower body temperature in mice and rats (Brittain and Handley, 1967;Bugajski and Zacny, 1980;Laverty and Taylor, 1969;Ozawa et al, 1977), opposite effects occur in rabbits (Cooper et al, 1965). Moreover, it was found that temperature changes produced by noradrenergic stimulation are dependent upon ambient temperature (AT).…”