[The effect of calcium-regulating hormones on pain sensitivity in rats]

Analgesic effect of calcitonin administered in doses of 1, 3, and 5 U/100 g was studied in rats. Intrathecal administration of calcitonin (0.015 U) results in higher increase in analgesic effect compared to intraventricular injection. Intramuscular (1, 3, and 5 U/100 g) and intraventricular (0.1 U) injection of parathormone exert no analgesic effect, whereas intrathecal injection in a dose of 0.1 U resulted in statistically significant analgesia. High correlation was found for nociception and calcium level in blood. Nifedipine and isoptin (1, 5, and 10 mg/kg) were shown to reduce significantly the analgesic effect of calcitonin. On the membrane of the isolated neuron of mollusk calcitonin (10(-9) - 10(-7) M) increased and in a concentration of 10(-6) M decreased JCa. Inhibiting effect of isoptin on JCa was found for combined action of calcitonin and isoptin on the neuron membrane.