title: Effects of dexmedetomidine on contractility, relaxation, and intracellular calcium transients of isolated ventricular myocardium.
abstract: The effects of the highly selective alpha 2-adrenoceptor agonist dexmedetomidine on contractility, relaxation, and the intracellular Ca2+ transients of isolated ventricular myocardium were studied in isolated right ventricular papillary muscles obtained from reserpinized ferrets. Dexmedetomidine (10(-10)-10(-5) M) did not alter amplitude and time variables of isometric, isotonic and zero-load-clamped twitches, except for a slight increase in maximal isotonic relaxation rate at 10(-5) M. Dexmedetomidine (10(-8)-10(-5) M) caused no changes in the intracellular Ca2+ transient detected with aequorin. These results suggest that dexmedetomidine has no intrinsic myocardial contractile effects.
authors.affiliation: Department of Anesthesiology, Mayo Foundation, Rochester, Minnesota 55905.
authors.forename: P R
authors.initials: PR
authors.lastname: Housmans
mesh_terms: D000316:Adrenergic alpha-Agonists / Q000494:pharmacology*; D000331:Aequorin; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D005289:Ferrets; D007093:Imidazoles / Q000494:pharmacology*; D008297:Male; D020926:Medetomidine; D009200:Myocardial Contraction / Q000187:drug effects*; D009206:Myocardium / Q000378:metabolism*; D010210:Papillary Muscles / Q000187:drug effects / Q000378:metabolism / Q000502:physiology
chemical_list: D000316:Adrenergic alpha-Agonists; D007093:Imidazoles; D000331:Aequorin; D020926:Medetomidine; D002118:Calcium