title: Interaction of cinepazide with adenosine on guinea-pig atria.
abstract: The negative inotropic effects of adenosine and adenine nucleotides, such as ATP and cAMP, on guinea-pig atria were selectively and dose-dependently augmented by cinepazide in concentrations insufficient to produce any effect alone (3 X 10(-5) M-3 X 10(-4)M). Adenosine (10(-5) M, 10 microCi) was degraded to inosine and hypoxanthine during incubation with atrial tissue. Cinepazide (3 X 10(-4) M) retarded the degradation of adenosine, and the formation of inosine and hypoxanthine. Incubation of the atrial tissue with adenosine (8.1 X 10(-9) M, 0.1 microCi) resulted in accumulation of 3H-activity. Cinepazide (3 X 10(-5) M-3 X 10(-4) M) inhibited this accumulation. These results suggest that cinepazide potentiates the negative inotropic effect of adenosine on guinea-pig atria by preventing both its degradation by deaminase and its accumulation by atrial tissue.
mesh_terms: D000241:Adenosine / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D004357:Drug Synergism; D005260:Female; D006168:Guinea Pigs; D066298:In Vitro Techniques; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects*; D010879:Piperazines / Q000494:pharmacology*; D011687:Purines / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D010879:Piperazines; D011687:Purines; D014665:Vasodilator Agents; C026896:cinepazide; D000241:Adenosine