Intrathecal porcine calcitonin enhances the release of [Met5]enkephalin-like material from the rat spinal cord.
Perfusion of the intrathecal space of halothane-anaesthetized rats with artificial cerebro-spinal fluid supplemented with porcine calcitonin (1-10 microM) produced a significant increase (+67-110%) in the spinal release of [Met5]enkephalin-like material. The effect of porcine calcitonin was markedly enhanced (+100%) in animals receiving a continuous i.v. infusion of the opioid antagonist naloxone (65 micrograms/kg per min). These data strongly suggest that the antinociceptive effect of intrathecal porcine calcitonin might involve a stimulatory action of the hormone on spinal enkephalinergic interneurones. In addition, presynaptic opioid autoreceptors probably control the activity of these neurones in the rat.
Collin
E
E
INSERM U288, Neurobiologie Cellulaire et Fonctionnelle, Faculté de Médecine Pitié-Salpêtrière, Paris, France.
Bourgoin
S
S
Gorce
P
P
Hamon
M
M
Cesselin
F
F
D000818:Animals; D002116:Calcitonin / Q000008:administration & dosage / Q000494:pharmacology*; D004744:Enkephalin, Methionine / Q000378:metabolism*; D007278:Injections, Spinal; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000378:metabolism*; D013552:Swine
D009270:Naloxone; D004744:Enkephalin, Methionine; D002116:Calcitonin