Reduced binding of 3H-reserpine to the hearts of 6-hydroxydopamine-pretreated rats

6-Hydroxydopamine (6-OH-DA) pretreatment of rats resulted in a consistent reduction of the small amounts of reserpine residual in the heart, 24 hr after its injection. This finding presumably depends on the destruction of sympathetic nerve terminals currently ascribed to 6-OH-DA and it indicates that reserpine in the heart is at least in part bound to adrenergic structures. The injection of harmaline and of 3H-inuline did not result in lower harmaline and tritium concentration in the hearts of 6-OH-DA pretreated rats.