The electrical transfer properties of basolateral-, luminal-, and gap junctional cell membrane in exocrine gland acinar cells.

1.对从大鼠胰腺酶促分离的单个腺泡细胞进行密封全细胞记录。采用相敏检测法同时记录细胞膜电容和电导的变化.乙酰胆碱（ACh，0.08 - 0.5 μ M）和八肽胆囊收缩素（CCK，10 - 50 pM）仅在EGTA（70 μ M）弱螯合胞浆Ca时，才同时引起细胞膜电流、电容和电导的瞬时增加。当用含有GTP-rS（GTP的稳定类似物，50 - 100 μ M）的溶液透析细胞时，这些反应被延长，而用含有GDP-bS（GDP的稳定类似物）的溶液透析细胞时，这些反应被抑制。这些结果表明，一种鸟嘌呤核苷酸结合蛋白（G蛋白）可能参与了乙酰胆碱或胆囊收缩素受体信号转导. ACh-或CCK-诱导的反应（有或没有GTP-rS在胞质溶胶）都废除时，高剂量的EGTA（1 - 2 mM）注射到腺泡细胞。此外，当胞质Ca被70 μ M EGTA弱缓冲时，A23187诱导持续的反应。这些结果表明，促分泌素通过增加和降低胞浆Ca浓度来调节细胞膜电容和电导的变化. ACh或CCK诱导的细胞膜电容的变化的峰值幅度，有或没有GTP-rS在胞质溶胶中，变化在200和1000 fF之间，从而表明20至100酶原颗粒可以与腔细胞膜融合，在这些激动剂，在大鼠胰腺外分泌腺泡细胞。

1. Single acinar cells, enzymatically isolated from the rat pancrease, were subjected to tight-seal whole-cell recordings. Changes in cell membrane capacitance and conductance were simultaneously recorded using a phas-sensitive detection method.2. Acetylcholine (ACh, 0.08 - 0.5 uM) and cholecystokinin - octapeptide (CCK, 10 - 50 pM) concomitantly induced transient increases in cell membrane current, capacitance and conductance only when cytosolic Ca was weakly chelated by EGTA (70 uM). These responses were prolonged when the cells were dialyzed with a solution containing GTP-rS (a stable analogue of GTP, 50 - 100 uM) whereas they were inhibited by dialyzing with that containing GDP-bS (a stable analogue of GDP). These results suggest that a type of guanine-nucleotide binding proteins (G-protein) could be involved in ACh-or CCK-receptor signalling.3. The ACh- or CCK-induced responses (with or without GTP-rS in the cytosol) were all abolished when a high dose of EGTA(1 - 2 mM) was injected into the acinar cells. In addition, A23187 induced sustained responses when the cytosolic Ca was weakly buffered by 70 uM EGTA. These results suggest that the secretagogoues regulate the changes in cell membrane capacitance and conductance via an increase and decrease of cytosolic Ca concentration.4. The peak amplitude of changes in cell membrane capacitance induced by ACh or CCK, with or without GTP-rS in the cytosol, varied between 200 and 1000 fF, thereby suggesting that 20 to 100 zymogen granules can fuse with the luminal cell membrane in response to these agonists, in rat exocrine pancreatic acinar cells.