Mechanism of reciprocal control of the autonomic nervous system by VIP-and vasopressin-neurons in the suprachiasmatic nucleus of the hypothalamus

颅内注射葡萄糖利用抑制剂2-脱氧-D-葡萄糖（2DG）可引起大鼠高血糖。在这种高血糖反应中，涉及投射到胰腺、肝脏和肾上腺的交感传出神经的兴奋，胰高血糖素和肾上腺素的血浆浓度的增加，以及血浆胰岛素浓度增加的抑制。在双侧视交叉上核（SCN）损伤的大鼠和盲大鼠中，颅内注射2DG未观察到高血糖反应。根据这些事实，我们研究了SCN中含有血管活性肠肽（VIP）的神经元在这些反应中的作用，因为VIP神经元接受视网膜神经输入。因此，观察到投射到肾上腺的交感传出神经的兴奋和由颅内注射2DG引起的高血糖被SCN的双侧病变消除，并且颅内注射VIP挽救了这些反应。VIP反义寡核苷酸抑制SCN内VIP的表达，可消除2DG颅内注射引起的高血糖反应，提示SCN内VIP神经元参与了2DG颅内注射引起的高血糖反应，SCN内存在精氨酸加压素（AVP）和生长抑素（SS）神经元。颅内注射AVP可抑制2DG引起的交感神经兴奋和高血糖，而注射AVP拮抗剂可增强2DG引起的交感神经兴奋和高血糖，颅内注射SS也有类似的作用。如果是这样的话，这些神经肽对自主神经系统的相互控制机制是什么，现在正在研究中。

Intracranial injection of 2-deoxy-D-glucose (2DG), an inihibitor of glucose utilization, caused hyperglycemia in rats. In this hyperglycemic response, exitations of sympathetic efferents projected to pancreas, liver and adrenal, increases in plasma concentrations of glucagon and adrenaline, and a suppression of the increase in the plasma insulin concentration are involved. In rats with bilateral lesions of the suprachiasmatic nucleus (SCN) and blind rats the hyperglycemic response to intracranial injection of 2DG was not observed. From these facts we examined the role of neurons containing vasoactive intestinal peptide (VIP) in the SCN in these responses because the VIP-neurons receive retinal neural inputs. Consequently, it was observed that the excitation of sympathetic efferents projected to the adrenal and the hyperglycemia elicited by intracranial injection of 2DG were eliminated by bilateral lesions of the SCN and intracranial injection of VIP rescued these responses. Furthermore, it was observed that inhibition of the expression of VIP in the SCN caused by antisense oligodeoxynucleotide to VIP mRNA eliminated the hyperglycemic response due to intracranial injection of 2DG.These facts indicate that neurons containing VIP in the SCN are involved in the mechanisms of the responses to intracranial injection of 2DG.In the SCN there are neurons containing arginine vasopressin (AVP) and somatostatin (SS). It was also observed that intracranial injection of AVP suppressed and that of an AVP-antagonist enhanced the excitation of the sympathetic activity and hyperlgycemia induced by intracranial injection of 2DG,and it was reported that intracranial injection of SS caused similar effects to those elicited by that of AVP.Whether these functions of AVP and SS derives from neurons containing these neuropeptides in the SCN,and if so what is the mechanism of the reciprocal control of the autonomic nervous system due to these neuropeptides are now under investigation.