The mechanism by which clonidine suppresses plasma renin activity (PRA) was investigated in dogs anesthetized with pentobarbital. Injection of clonidine (1 micrograms/kg) into the cisterna magna decreased PRA from levels stimulated by prior hemorrhage into a blood reservoir to reduce mean blood pressure by 25% (21.7 ng/ml/hr +/- 6.6 SE leads to 11.1 ng/ml/hr +/- 2.4 SE; p less than 0.05). Cloni...

Pressor responses to intracerebroventricular (i.c.v.) injection of clonidine were investi gated in conscious spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY). Clonidine (1-10 ,ug, i.c.v.) caused a dose-dependent pressor response and decrease in heart rate in both SHR and WKY. In SHR, low doses (1, 2.5 ug) but not high doses (5, 10 jig) of i.c.v.-clonidine in duced ...

Preemptive analgesia refers to blockade of afferent nerve fibers before a painful stimulus, which prevents or reduces subsequent pain even beyond the effect of the block. The aim of the study was to compare the effect of clonidine used before and at the end of operation on pain control in abdominal surgery. A total of 77 patients admitted for colorectal surgery were randomly classified into thr...

After completion of abdominal aortic graft, 29 patients received an i.v. infusion of placebo (n = 16) or clonidine 7 micrograms kg-1 (n = 13) over 120 min in a double-blind study. Cardiovascular variables were measured and plasma samples obtained up to 5 h after arrival in the recovery room, for assay of noradrenaline, adrenaline, vasopressin and renin concentrations. Noradrenaline, adrenaline ...

In a prospective, double-blind, controlled study the efficacy of clonidine was assessed in children, with respect to sedation, intubation response, and recovery. Fifty children, aged 4-12 years, undergoing general anesthesia were studied. Twenty-five children (group I) received oral diazepam) 0.2 mg/kg and another 25 children (group II) received oral clonidine 3 micrograms/kg, 90-120 minutes be...

Background: Many intrathecal adjuvants are being used with local anesthetics to prolong the intraoperative anesthesia and postoperative analgesia. Clonidine buprenorphine known potentiate effects of anesthestics. Aims Objectives: This study was designed compare duration analgesia as well sensory motor block onset, hemodynamic changes, perioperative complications between clonidine when an adjuva...

in this study, the effect of α-adrenoceptor agents on imipramine-induced antinociception was investigated using formalin test. intraperitoneal (i.p.) administration of imipramine at different doses (10-80 mg/kg) induced antinociception in both phases of formalin test. in addition, intracerebroventricular (i.c.v.) injection of imipramine (1, 5, and 10 µg/rat) did not elicit any effect, although ...

The effects of clonidine on substance P (SP) binding was investigated using rat brain and spinal cord membrane preparations preincubated with various concentrations of clonidine. [3H]SP specific binding in the spinal cord was significantly decreased with 10(-4) M clonidine, but no effect on binding was seen in the brain. Scatchard analysis of SP binding indicated that Bmax was significantly dep...