the positive inotropic potencies of twelve compounds on contracting guinea pig left atria correlated well with the equilibrium dissociation constants ( kd values ) from the inhibition of [ 3h ] ouabain binding to guinea pig cardiac ( na+ + k+ ) -atpase ( r = 0.98 for seven 5 beta-compounds , r = 0.95 for five 5 alpha-compounds ) .
C0225860
left atria
C0018787
cardiac