Responses of preoptic thermosensitive neurons to poikilothermia-inducing peptides--bombesin and neurotensin.

Microelectrophoretic application of bombesin (BS) and neurotensin (NT) to thermosensitive and non-thermosensitive neurons in the preoptic and anterior hypothalamus (PO/AH) of anesthetized rats depressed the activity of 78 (54.2%) of 144 neurons and that of 66 (51.6%) of 128 neurons, respectively. The depressing effects of both peptides which were uniformly observed across warm-sensitive and cold-sensitive neurons in the PO/AH are consistent with their poikilothermic actions.