The significance of Gprotein-gated inwardly rectifying K^+ channel in the anterior pituitary endcrine cells

垂体前叶内分泌细胞G蛋白门控内向整流K^通道的意义

• 批准号: 09671680
• 负责人: MORISHIGE Kenichiro
• 金额: $ 1.98万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09671680/
• 关键词: potassium channel; pituitary; patch-clamp; TRH; dopamine; TSH; capacitance; RT-PCR; パッチクランプ; TRHドパミン; TSH膜容量; 電子顕微鏡

G protein-gated inwardly rectifying K+ (K_G) channel, a member of inwardly rectifying K^+ channel, is directly activated by pertussis toxin-sensitive G proteins.In endocrine organs, i.e., the anterior pituitary lobe, it was reported that some neurotransmitters including dopamine and somatostatin hyperpolarize the membrane by activating K_G channels, which results in the inhibition of hormone secretion.We found GIRK1 (Kir3.1), the main subunit of K_G channels, to be localized predominantly on the membranes of intracellular dense core vesicles which contained thyrotropin.Stimulation of these thyrotroph cells with thyrotrpin-releasing-hormone provoked fusion of vesicles to the plasma membrane, increased expression of GIRK1 subunit in the plasma membrane, and markedly enhanced K_G currents stimulated by dopamine and somatostatin.These data indicate a novel mechanism for the rapid insertion of functional ion channels into the plasma membrane, which could form a new type of negative feedback control loop for hormone secretion in the endocrine system.