Effects of Noradrenaline and 5－hydroxytryptamine on Thermoresponsive Neurons in Slice Preparations of Rat Brainstem

Effects of Noradrenaline and 5－hydroxytryptamine on Thermoresponsive Neurons in Slice Preparations of Rat Brainstem

Creators Watanabe Tatsuo

Noradrenaline (NA) and 5-hydroxytryptamine (5-HT) have been thought to be involved in thermoregulation. In the present study, using slice preparations. We observe that NA inhibits the activities of most of the warm-responsive neurons but that 5-HT facilitates those of most of the warm-responsive neurons in the preoptic and anterior hypothalamic region. This conclusion supports the previous which show that the serotonergic system activates heat-loss responses and that NA inhibits heat-loss responses during heat expouse.On the other hand, the result obtained in the dorsal raphe nucleus was opposite to that in the preopic and anterior hypothalamic region when 5-HT was applied. This observation may be in part related to the autoregulation of 5-HT containing neurons in the dorsal raphe nucleus. In addition, the dose-response relations were determined using in vitro slice preparations. In both regions, NA and 5-HT started to effect the activities of the warm-responsive neurons at minimum concentration of 5×1０　mol, while the maximum responses were obtained at a concentration of 5×10 mol.

[ISSN]0513-1812

[NCID]AA00594272