Subarachnoid injection of salmon calcitonin does not induce analgesia in rats.
It has been proposed that the polypeptide calcitonin (CT) occurs in the central nervous system and may have a neuromodulatory role in endogenous pain relief pathways. However, recent results suggest that CT is not present in the central nervous system. Intrathecal (IT) injection of CT on the lumbar enlargement of rats caused a reversible increase of the hindpaw lick latency in the hot plate test. No analgesia was observed with the vocalization test to electrical stimulation of the tail. In contrast 10 micrograms morphine hydrochloride IT caused analgesia in both tests. It is concluded that IT CT does not cause analgesia, but has a reversible blocking effect on motor responses.
D000698:Analgesia; D000818:Animals; D002116:Calcitonin / Q000494:pharmacology*; D007267:Injections; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013346:Subarachnoid Space
C028815:salmon calcitonin; D002116:Calcitonin