Gokin A P, Jennings L J, Mawe G M
Department of Anatomy and Neurobiology, University of Vermont, Burlington, USA.
Am J Physiol. 1996 Nov;271(5 Pt 1):G876-83. doi: 10.1152/ajpgi.1996.271.5.G876.
The actions of calcitonin gene-related peptide (CGRP) have been determined from intracellular recordings obtained from gallbladder neurons in intact whole mount preparations. In most cells, pressure microejection of CGRP elicited a slow, monophasic depolarization, 4 mV in amplitude, that was associated with a decrease in input resistance and increased excitability. The CGRP-induced depolarization was attenuated in a low-Na+ solution and had a reversal potential of -8 mV. In 10% of the cells, microejection of CGRP elicited a biphasic response that was composed of a rapid transient depolarization followed by a slow depolarization that was similar to the monophasic response. Addition of CGRP (1-10 nM) to the bathing solution elicited a monophasic depolarization and desensitized the cells to applications of CGRP by microejection. Forskolin, applied either by microejection or bath application, also depolarized gallbladder neurons and produced cross-desensitization to CGRP. Responses to substance P were not enhanced by CGRP, and CGRP did not affect fast synaptic responses. It is concluded that CGRP may contribute to a local axon reflex response in gallbladder ganglia.
降钙素基因相关肽（CGRP）的作用已通过在完整整装标本中对胆囊神经元进行细胞内记录来确定。在大多数细胞中，通过压力微喷射CGRP会引发缓慢的单相去极化，幅度为4 mV，这与输入电阻降低和兴奋性增加有关。CGRP诱导的去极化在低钠溶液中减弱，反转电位为-8 mV。在10%的细胞中，微喷射CGRP会引发双相反应，该反应由快速短暂去极化和随后类似于单相反应的缓慢去极化组成。向浴液中添加CGRP（1-10 nM）会引发单相去极化，并使细胞对通过微喷射施加的CGRP脱敏。无论是通过微喷射还是浴浴施加福斯可林，也会使胆囊神经元去极化，并对CGRP产生交叉脱敏。CGRP不会增强对P物质的反应，且CGRP不影响快速突触反应。结论是CGRP可能有助于胆囊神经节中的局部轴突反射反应。
