we investigated the effects of adenosine on the positive chronotropic and inotropic responses to an endogenous catecholamine ( norepinephrine ) , a beta 1-adrenoceptor agonist ( dobutamine ) , an adenylate cyclase activator ( forskolin ) , a phosphodiesterase inhibitor ( 3-isobutyl-1-methylxanthine , ibmx ) and a calcium channel agonist ( bay k 8644 ) in the isolated , blood-perfused dog atrium .
C1372804
positive chronotropic
C0028351
norepinephrine