Study of the biochemical processing of the biowarning information through the hypothalamu

本研究旨在研究应激刺激下大鼠血清素（5HT）和去甲肾上腺素（NA）水平的动态变化，得出以下结论：(1)固定应激引起的厌食症与下丘脑5HT释放的立即增加有关。注射5HT受体拮抗剂可显著降低固定诱导的厌食症，提示应激时下丘脑5 -羟色胺能系统被激活，5HT在摄食行为中是一种抑制递质。(2)固定升高内侧前额叶皮质（PFC） NA水平。预注射苯二氮卓受体激动剂地西泮可显著减弱固定诱导的NA释放，而注射一种致焦虑化合物FG7142可促进非应激条件下NA的释放。因此，应激刺激激活内侧PFC中的NA系统，这可能通过激活大脑中的苯二氮卓类受体来调节。(3)固定应激快速增加脾脏NA水平，同时抑制自然杀伤（NK）细胞毒性。手术切除脾交感神经后，NA水平的升高和NK细胞毒性的抑制均显著减弱，表明固定诱导的脾N/K细胞毒性的抑制主要是通过脾交感神经活性的增强来介导的。这些结果表明5HT和NA都可能作为神经递质和/或神经调节剂来调节生物报警过程。

This study was designed to study the dynamic changes in serotonin (5HT) and noradrenaline (NA) levels during the stressful stimuli, and have reached the following conclusions in rats. (1) Immobilization-stress caused anorexia in conjunction with an immediate increase in thehypothalamic 5HT release. Injection of 5HT receptor antagonist significantly reduced the immobilization-induced anorexia, suggesting that the hypothalamic serotonergic ystem is activated during stress and 5HT is an inhibitory transmitter in feeding behavior. (2) Immobilization elevated NA levels in the medial prefrontal cortex (PFC). Pre-injection of a benzodiazepine receptor agonist, diazepam, significantly attenuated the immobilization-induced NA release, while the injection of an anxiogenic compound, FG7142, facilitated it in non-stressed condition. Thus the stressfull stimuli activate the NA system in the medial PFC which may be modulated by an activation of the benzodiazepine receptors in the brain. (3) Immobilization-stress rapidly increased NA levels of spleen in conjunction with the suppression of natural killer (NK) cytotoxicity. Both theincreased levelsof NA ad he suppresion of NK cytotoxicity were significantly attenuated after surgical denervation of the splenic sympathetic nerve, indicating that immobilization-induced suppression of splenic N/K cytotoxicity was mediated predominantly through enhanced activity of the splenic sympathetic nerve..These results suggest that both 5HT and NA may act asneurotransmitters and/or neuromodlators which regulate biowarning processes in the living body.