NEUROENDOCRINOLOGICAL ROLES OF HISTAMINE IN THE HYPOTHALAMO-HYPOPHYSEAL SYSTEM

从我们实验室研究的大鼠脑内组胺能神经元系统的分布来看，认为组胺作为神经调节剂在下丘脑-垂体神经内分泌系统中起着重要的作用。为了了解其在神经内分泌调节中的作用，我们研究了生理刺激垂体激素分泌后下丘脑组胺浓度的变化，以及使用组氨酸脱羧酶特异性抑制剂α -氟甲基组氨酸（FMH）消耗神经元组胺对血浆激素水平的影响。结果如下：1。在含有组胺能神经元细胞体的下丘脑后区，我们发现组胺含量有明显的昼夜节律。慢性静脉注射FMH后，血浆皮质酮水平的明显日变化减弱。双侧肾上腺切除术导致下丘脑后部组胺含量降低，下丘脑前部组胺含量升高。慢性ig给药FMH后，双侧肾上腺切除术后血浆ACTH的明显升高被完全抑制。高渗生理盐水引起血浆加压素水平和下丘脑组胺含量升高。长期给药可抑制生理盐水引起的血浆抗利尿激素升高。此外，通过体外顺序灌注系统，我们发现<H_1> -受体参与rh - rh分泌。此外，我们使用一种更灵敏的检测组胺能末端的方法检查了大鼠大脑中组胺能末端的详细分布，发现下丘脑核（如室旁核和视上核、正中隆起和神经垂体）中的纤维密集网络。这些神经化学和组织化学的发现支持了我们的假设，即组胺是神经内分泌系统中的神经调节剂。

From the distribution of the histaminergic neuron system in rat brain, elucidated in our laboratory, it is considered that histamine plays some important roles as a neuromodulator in the hypothalamo-hypophyseal neuroendocrine system. To know its roles in the neuroendocrine regulation, we studied changes in histamine concentration in the hypothalamus after physiologically stimulating hypophyseal hormone secretion and effects of depletion of neuronal histamine using alfa-fluoromethylhistidine (FMH), a specific inhibitor of histidine decarboxylase, on the hormone level in plasma. The results are as follows.1. In the posterior hypothalamic area which contains cell bodies of the histaminergic neurons, we found a clear circadian rhythm in histamine contents. After chronic i.c.v. administration of FMH, the clear diurnal variation of the plasma corticosterone levels was diminished.2. Bilateral adrenalectomy caused decrease of histamine contents in the posterior hypothalamus and increase of those in the anterior hypothalamus. After chronic i.p. administration of FMH, the marked increase of plasma ACTH by bilateral adrenalectomy was completely suppressed.3. Administration of hyperosmotic saline caused increase of both plasma vasopressin levels and hypothalamic histamine contents. Chronic administration of FMH i.c.v. suppressed the increase of plasma vasopressin induced by the saline injection.In addition, using in vitro sequential perifusion system, we found involvement of <H_1> -receptor in LH-RH secretion. Furthermore, we examined the detailed distribution of histaminergic terminals in the rat brain using a more sensitive method for detecting histaminergic terminals, and found that dense networks of the fibers in the hypothalamic nuclei, such as the paraventricular and supraoptic nucleus, the median eminence, and neurohypophysis.These neurochemical and histochemical findings support our hypothesis, that is, histamine is a neuromodulator in the neuroendocrine system.