Role of catecholamines in calcitonin-induced analgesia.

The possibility that the catecholaminergic (CA) system might be involved in calcitonin (CT)-induced analgesia was examined. The administration of the neurotoxin for CA neurons, 6-hydroxydopamine (6-OHDA) significantly reduced salmon CT (sCT) analgesia as measured in rats by the hot-plate test. Pretreatment with an alpha- and beta-blocker (phentolamine and propranolol) was also effective in lowering significantly the activity of sCT. When the two drugs were administered alone, propranolol, but not phentolamine, reduced the analgesic effect of sCT. A more pronounced and long-lasting inhibitory effect on sCT-analgesia was obtained using atenolol (selective beta 1-receptor blocker). The present data support the role of the CA system in sCT-induced analgesic activity.