title: Effects of dexmedetomidine, a selective alpha 2-adrenoceptor agonist, on hemodynamic control mechanisms.
abstract: Dexmedetomidine, a selective alpha 2-adrenoceptor agonist, was administered to five healthy male volunteers in single intravenous doses of 12.5, 25, 50, and 75 micrograms as part of a placebo-controlled study. The drug caused dose-dependent decreases in systolic and diastolic blood pressure. A small initial hypertensive response was observed after injection of the two highest doses. Heart rate was decreased. The concentration of norepinephrine in plasma was decreased significantly (by up to 92%), and the decrease was dose-dependent. No significant drug-induced alterations were observed in plasma renin activity or in the concentrations of atrial natriuretic peptide and arginine vasopressin in plasma. Other drug effects included dose-dependent impairment of vigilance and stimulation of growth hormone secretion. Plasma cortisol levels were unaffected. Dexmedetomidine is a potentially useful tool for studies of the physiology and pharmacology of alpha 2-adrenoceptors in human beings and may have therapeutic applications in clinical conditions in which sedative and sympatholytic effects are considered beneficial, such as premedication for anesthesia and surgery.
authors.affiliation: Department of Pharmacology, University of Turku, Finland.
authors.forename: A
authors.initials: A
authors.lastname: Kallio
authors.forename: M
authors.initials: M
authors.lastname: Scheinin
authors.forename: M
authors.initials: M
authors.lastname: Koulu
authors.forename: R
authors.initials: R
authors.lastname: Ponkilainen
authors.forename: H
authors.initials: H
authors.lastname: Ruskoaho
authors.forename: O
authors.initials: O
authors.lastname: Viinamäki
authors.forename: H
authors.initials: H
authors.lastname: Scheinin
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000328:Adult; D001127:Arginine Vasopressin / Q000097:blood; D009320:Atrial Natriuretic Factor / Q000097:blood; D001794:Blood Pressure / Q000187:drug effects*; D002851:Chromatography, High Pressure Liquid; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine; D009638:Norepinephrine / Q000097:blood; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects; D012083:Renin / Q000097:blood; D013237:Stereoisomerism
chemical_list: D000316:Adrenergic alpha-Agonists; D007093:Imidazoles; D011942:Receptors, Adrenergic, alpha; D001127:Arginine Vasopressin; D009320:Atrial Natriuretic Factor; D012083:Renin; D020926:Medetomidine; D006854:Hydrocortisone; D009638:Norepinephrine