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

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