The hypothermic action of carbachol in the rat brain periaqueductal grey area may involve neurotensin

Abstract
1 Neurotensin (NT) and carbachol both caused hypothermia when injected into the periaqueductal grey area (PAG) of rat brain. 2 Atropine prevented carbachol- but not NT-induced hypothermia. 3 NT-induced hypothermia was unaffected by various neurotransmitter agonists and antagonists in the PAG. 4 Both NT antibodies and thyrotrophin releasing hormone prevented carbachol hypothermia. 5 It is concluded that the hypothermic action of carbachol in the PAG is mediated via endogenous NT.