The effect of a potent inhibitor of platelet aggregation,
BL-3459, on
adrenaline-induced myocardial
necrosis was investigated in beagle dogs.
BL-3459, an
alpha-adrenergic receptor blocking agent,
phenoxybenzamine, and a
beta-adrenergic receptor blocking agent,
propranolol, were compared for their ability to modify the effects of
adrenaline on platelet function, arterial blood pressure and myocardial damage.
Adrenaline infusion led to a dose-related myocardial damage, elevation in arterial blood pressure, elevation in screen filtration pressure (
SFP) and fall in platelet count.
BL-3459 inhibited the elevation in
SFP and the fall in platelet count as well as limiting the extent of myocardial damage.
Phenoxybenzamine significantly modified all
adrenaline-induced changes except the elevation in
SFP.
Propranolol had little effect alone and seemed to antagonize the beneficial effects of
BL-3459 when the two drugs were combined. These results suggest that while other factors may also be involved, platelet aggregation and transient
hypertension are correlated with the extent of
adrenaline-induced myocardial
necrosis observed in this model. A potent inhibitor of platelet aggregation,
BL-3459, and the
alpha-adrenergic receptor blocking agent,
phenoxybenzamine, appear to afford protection against the observed pathological effects.