Cardiac uptake kinetics and possible dynamic effects of a new cerebral antiischaemic compound FG 9202 (NBQX) studied in the isolated rabbit heart.
Accumulation of the putative drug FG 9202 in isolated rabbit hearts showed monophasic exponential kinetics with a half-life of only 0.59 min. The disposition showed a three-phasic exponential time course with half-lives of 0.34, 1.51 and 15.8 min, respectively, which was interpreted as three-compartment kinetics. FG 9202 accumulated only about 3 times in the myocardium at steady-state with 51, 32 and 17% referable to a superficial and two deeper myocardial drug pools. The drug did not significantly affect contraction amplitude or velocity of contraction at increasing concentrations up to 40.6 micrograms.ml-1 (119 microM). Heart beating frequency decreased slightly but only significantly at some of the higher concentrations. Neither dromotropic, bathmotropic nor ischaemic ECG-effects were observed. Coronary flow-rate and myocardial oxygen consumption decreased at the highest drug concentrations. Myocardial efficiency expressed as the ratio of contractile parameters to oxygen consumption showed a minor but insignificant increase at the highest drug-exposure levels. Our findings indicate that FG 9202 is not potentially toxic to the isolated, spontaneously beating rabbit heart in vitro.
Nielsen-Kudsk
F
F
Institute of Pharmacology, University of Aarhus, Denmark.
Mellemkjaer
S
S
Bang
L
L
D000818:Animals; D003326:Coronary Circulation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000187:drug effects; D005260:Female; D006321:Heart / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism*; D010101:Oxygen Consumption / Q000187:drug effects; D010477:Perfusion; D011810:Quinoxalines / Q000493:pharmacokinetics* / Q000494:pharmacology; D011817:Rabbits
D011810:Quinoxalines; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline