urapidil dose-dependently antagonized the tachycardic effect of isoprenaline at beta 1-adrenoreceptors ( pdr2 5.1 ) but also exhibited intrinsic activity by increasing basal heart rate ( maximum effect of urapidil was 30 % of that of isoprenaline ) .
C0039231
tachycardic
C0022245
isoprenaline