The role of astrocyte VRAC in the rebound excitation of vasopressin neurons evoked by acute hyponatremic stimulation in rats and the underlying mechanisms
作者单位：Department of PhysiologyBasic Medical SchoolHarbin Medical University
会议名称：《2019中国生理学会学术年会暨张锡钧基金第十五届全国青年优秀生理学学术论文交流会及第十三届全国青年生理学工作者学术会议》
会议日期：2019年
学科分类：1002[医学-临床医学] 100201[医学-内科学(含：心血管病、血液病、呼吸系病、消化系病、内分泌与代谢病、肾病、风湿病、传染病)] 10[医学]
关 键 词：astrocyte supraoptic nucleus vasopressin VRAC volume
摘 要：Objective Acute hyponatremia is one of the common complications of water retention *** development is often accompanied increased secretion of vasopressin(VP), which further aggravates brain *** reported, VP secretion from VP neurons is under close regulation of their adjacent astrocytes, and the activity of volume-regulated anion channel(VRAC)is one key factor that determines the regulatory volume decrease(RVD)/retraction of astrocyte processes around VP neurons following their initial extension in response to hyposmotic *** this study, we report the role of astrocyte VRAC in the rebound excitation of VP neurons evoked by hyposmotic stimulation in brain slices of *** addition, we also analyzed the association between VRAC activity and other volume-regulating proteins, such as aquaporin-4(AQP4) and glial fibrillary acidic protein(GFAP).Methods Adult male rats were used in this study in brain slices containing the supraoptic nucleus(SON).Path-clamp recordings were used for evaluating the effect of blocking VRAC on the electrical activities of VP *** blots and fluorescent immunohistochemistry were used for analyzing the expression of astrocytic volume-associated *** Hyposmotic stimulation caused a rebound excitation in VP neurons following a short period of *** rebound excitation was blocked by pre-application of specific VRAC blockers DIDS(200 nm) or phloretin(30μM).Moreover, blocking the VRAC with phloretin also changed phloretin-modulated pattern of AQP4 and GFAP expressions following hyposmotic ***: These results indicate that activation of astrocytic VRAC is responsible for the rebound excitation in VP neurons in acute hyponatremic stimulation, which is correlated with the activity of AQP4 and GFAP.