Effect of clonidine on changes in plasma catecholamine concentrations and oxygen consumption caused by the cold pressor test.
This study was designed to investigate whether clonidine could attenuate the increase in oxygen consumption (VO2), arterial pressure (AP) and plasma catecholamines in response to the cold pressor test (CPT), an intense stimulation of the sympathetic nervous system. Six volunteers were given clonidine (2 micrograms kg-1 and 4 micrograms kg-1) and placebo i.m. in a random, double-blind, cross-over manner. Both clonidine doses decreased plasma catecholamine concentrations (P < 0.01), but only the higher dose of clonidine attenuated the CPT-induced absolute increase in plasma catecholamine concentration compared with the placebo group (P < 0.01). VO2 and AP decreased and were less after clonidine 4 micrograms kg-1 when compared with clonidine 2 micrograms kg-1 and placebo (P < 0.05) throughout the observation period. Thus, although clonidine 4 micrograms kg-1 attenuated the catecholamine response, the increases in VO2 and AP in response to CPT were similar in all groups.
Taittonen
M T
MT
Department of Anaesthesiology, Turku University Hospital, Finland.
Aantaa
R
R
Kirvelä
O A
OA
D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000328:Adult; D000959:Antihypertensive Agents / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002245:Carbon Dioxide / Q000378:metabolism; D003000:Clonidine / Q000494:pharmacology*; D003080:Cold Temperature; D018592:Cross-Over Studies; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D004837:Epinephrine / Q000097:blood*; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D009638:Norepinephrine / Q000097:blood*; D010101:Oxygen Consumption / Q000187:drug effects*; D013565:Sympatholytics / Q000494:pharmacology
D000316:Adrenergic alpha-Agonists; D000959:Antihypertensive Agents; D013565:Sympatholytics; D002245:Carbon Dioxide; D003000:Clonidine; D009638:Norepinephrine; D004837:Epinephrine