To elucidate the mechanism of antinociceptive effects of calcitonin, we investigated whether receptor antagonists for various neurotransmitter receptors alter the inhibitory effect of calcitonin on intrathecally injected N-methyl-d-aspartate-induced aversive behavior in mice. Neither naloxone, an opioid receptor antagonist, phentolamine and benextramine, α-adrenoceptor antagonists, nor ritanserin, a 5-HT2A receptor antagonist, inhibited the calcitonin-induced anti-aversive effects. Pindolol and (-)-propranolol, non-selective antagonists of β-adrenoceptors and 5-HT1 receptors, 1-(2-methoxyphenyl)-4-[4-(2-phethalimido) butyl]-piperazine hydrobromide (NAN-190), a 5-HT1A receptor antagonist, 3-tropanyl-3,5-dichlorobenzoate (MDL72222) and metoclopramide, 5-HT3 receptor antagonists, significantly inhibited the calcitonin-induced anti-aversive effects. (-)-Bicuculline, a GABAA receptor antagonist, phaclofen and 5-aminovaleric acid, GABAB receptor antagonists, also attenuated the calcitonin-induced anti-aversive effects. These results suggest that β-adrenoceptor, 5-HT1A, 5-HT3, GABAA and GABAB receptors, but not α-adrenoceptor, opioid nor 5-HT2A receptors, are involved in the inhibitory effect of calcitonin on intrathecally injected N-methyl-d-aspartate-induced aversive behavior in mice.
All Science Journal Classification (ASJC) codes