6-Hydroxydopamine treatment increases beta-adrenoceptors and Ca2+ channels in rat heart.

Rats received 6-hydroxydopamine (50 mg/kg i.v.) on two successive days. After 14 days cardiac beta-adrenoceptors and Ca2+ channels were measured by radioligand binding. Ca2+ channel binding [( 3H]nitrendipine) was increased 31% with no change in affinity, and beta-adrenoceptor binding [( 3H]dihydroalprenolol) was increased 28% with no change in affinity. Innervation may be important in the regulation of Ca2+ channel expression.