Effect of adenosine on atrioventricular conduction. I: Site and characterization of adenosine action in the guinea pig atrioventricular node.

Guinea pig heart preparations (isolated AV node preparations n=16, isolated perfused hearts n=17)

Adenosine (dose-dependent, up to >20 microM, and 5.7 microM) and adenosine agonists (N6-cyclopentyladenosine, N6-(L-2-phenyl-isopropyl)adenosine, 5'-N-ethylcarboxyamidoadenosine, 2-chloroadenosine) with or without uptake/deamination inhibitors (dipyridamole and erythro-9-(2-hydroxy-3-nonyl)adenine)

Site of adenosine-induced AV conduction block, effect of uptake/deamination on concentration-negative dromotropic effect, and the mediating adenosine receptorsurrogate