REGULATION OF PERIPHERAL AUTONOMIC FUNCTION AND NEUROENDOCRINE RESPONSES

本项目的主要目标是确定 儿茶酚胺及其受体在调节运动的大脑功能中的作用 活动、神经内分泌和自主神经功能。级别 特定脑细胞外液中的单胺类物质及其代谢产物 使用体内微透析来监测这些区域。微渗析探头 通过附连的输液，微导管提供了一种引入 微透析区的药物或同位素标记化合物 探测器。去甲肾上腺素及其代谢产物在不同时间的释放量 下丘脑内的核团与反应的程度有关。 外周交感-肾上腺髓质系统与垂体 肾上腺皮质轴。在下丘脑，制动诱导 去甲肾上腺素局部释放的增量由全身性增加 给药育亨宾，一种α2-肾上腺素能受体阻滞剂。 在纹状体，我们估计多巴胺的释放，重新摄取和 微渗析与示踪动力学相结合的代谢研究 使用的同位素稀释技术类似于 血浆。脑室注射6-羟基多巴胺的大鼠 回收的[~3H]-DA的比活力与小鼠的相似 灌流，而具有特定活动的完整动物则减少 大约100倍。同时获得特定活动的值 [~3H]-二羟基苯乙酸([~3H]-DOPAC)和[~3H]-高香草酸 大约是DA的十分之一，这表明DA在很大程度上是 释放前的神经元。 孤束核(NTS)，位于延髓内侧。 脑干，构成传入终止的主要部位。 动脉压力感受器。大鼠孤束核神经元单位放电的研究 麻醉兔后，我们发现大多数NTS神经元的放电增加 静脉注射后的比率。注射苯肾上腺素，这会增加血压 通过刺激血管平滑肌上的α1-肾上腺素能受体产生急性反应 细胞。相反，PVN的电刺激通常会减少 NTS放电和减弱或阻止去甲肾上腺素引起的大鼠脑内兴奋性兴奋 NTS发射。结果支持了一种急性重置的模型 在情绪低落时会有压力反射。

The main objectives of this project are to determine the roles of catecholamines and their receptors in brain functions that regulate motor activity, neuroendocrine secretion, and autonomic function. Levels of monoamines and their metabolites in extracellular fluid in specific brain regions are monitored using in vivo microdialysis. Microdialysis probes with an attached infusion microcannulae provides a means for introducing drugs or isotopically-labeled compounds in the region of the microdialysis probe. The magnitude of release of NE and its metabolites in different nuclei within the hypothalamus is related to the degree of responses of the peripheral sympatho-adrenal medullary system and pituitary adrenocortical axis. In the hypothalamus, immobilization-induced increments in local release of norepinephrine are increased by systemic administration of yohimbine, an alpha2-adrenergic receptor blocking agent. In the striatum, we estimate the rate of dopamine release, reuptake and metabolism by combining microdialysis and tracer kinetics of[3H]-DA and using isotope dilution techniques similar to those being used in the plasma. In rats treated intracerebroventricularly with 6-hydroxydopamine the specific activity of recovered [3H]-DA is similar to that in the perfusate, whereas intact animals that had a specific activity was reduced about 100-fold. Simultaneously obtained values for the specific activities of [3H]dihydroxyphenylacetic acid ([3H]-DOPAC) and [3H]-homovanillic acid were about one-tenth of DA indicating that DA is largely deaminated within the neurons prior to release. The nucleus of the solitary tract (NTS), in the mediodorsal medulla of the brainstem, constitutes the main site of termination of afferents from arterial baroreceptors. In a study of single unit firing of NTS neurons in anesthetized rabbits, we found that most NTS neurons increase their firing rate after i.v. injection of phenylephrine, which increases blood pressure acutely by stimulating alpha1-adrenoceptors on vascular smooth muscle cells. In contrast, electrical stimulation of the PVN usually decreased NTS firing and attenuated or prevented phenylephrine-induced increases in NTS firing. The results support a model for acute resetting of the baroreflex during emotional distress.