生长抑素及质子泵抑制剂对大鼠胰腺腺泡细胞慢活化电压依赖性钾离子通道的影响

Effect of somatostatin and proton pump inhibitor on the slowly-activiting voltage-dependent K＋ channel in the rat pancreatic acini

目的通过检测慢活化电压依赖性外向钾离子通道电流（Iks）的变化，探讨生长抑素及质子泵抑制剂（PPI）对胰腺腺泡细胞慢活化电压依赖性钾离子通道及胰腺外分泌的影响。方法分离SD大鼠胰腺组织，取得胰腺腺泡细胞悬液，用EPC10膜片钳放大器记录电压钳制下的不同组别胰腺腺泡细胞Iks的电流值并比较其间差异。分组如下：冲洗液处理为对照组，5umol／L和20umol／L293B组，5nmol／L促胰液素组，5nmol／L促胰液素＋100nmol／L或10nmol／L或1nmol／L生长抑素组，0．3mmol／L8溴-环单磷酸腺苷（8Br-cAMP）组，0．3mmol／L8Br—cAMP＋100nmol／L生长抑素组，1umol／L乙酰胆碱（Ach）组，1umol／LAch＋100nmol／L生长抑素组，5nmol／L促胰液素＋10^-5mol／L或10^-6mol／L或10^-7mol／L奥美拉唑组，1umol／LAch＋10^-5mol／L或10^-6mol／L或10^-7mol／L奥美拉唑组。组间比较采用单因素方差分析，P〈0．05为差异有统计学意义。结果大鼠胰腺腺泡细胞静息膜电位为（-40±0．8）mV，当去极化至＋10mV时，对照组的Iks为（420．0±3．2）pA。经5umol／L和20umol／L293B作用后，大鼠胰腺腺泡细胞Iks减少为对照组的（60．4±4．2）％和（30．2±3．1）％（F=6．87，P〈0．05）。5nmol／L促胰液素刺激后，Iks增加为（823．0±2．2）pA，分别加入100nmol／L、10nmol／L和1nmol／L生长抑素，Iks降低至（510．0±3．2）pA，（584．0±2．8）pA和（789．0±6．9）pA（F=5．67，P〈0．05）；分别加入10^-5mol／L、10^-6mol／L和10^-7mol／L奥美拉唑后，Iks峰值未见明显变化，分别为（806．5±3．6）pA，（814．8±3．2）pA和（816．3±2．9）pA（P〉0．05）。1umol／LAch刺激后，Iks的峰值为（966．0±3．2）pA；加入100nmol／L生长抑素后，Iks峰值为（942．0±6．3）pA；分别加入10^-5mol／L，10^-6mol／L和10^-7mol／L奥美拉唑后，其Iks峰值未见明显变化，分别为（956．3±10．3）pA，（957．5±8．6）pA和（960．0±8．4）pA（P〉0．05）。结论生长抑素能抑制胰腺腺泡细胞慢活化电压依赖性钾离子通道的开放，PPI对该通道没有明显抑制作用。

Objective To explore the effect and mechanism of somatostatin and proton pump inhibitor （PPI） on Iks in pancreatic acini （RPA） by testing the change of slowly-activiting voltage- dependent K^＋ channel current （Iks）. Methods Pancreatic acini was isolated and its suspension was obtained. Iks Values of different groups were recorded by an EPC10 patch clamp amplifier and the difference among the groups was compared. The groups were divided as followed： washing solution treated as control group, 5 umol/L or 20 umol/L 293B groups, 5 nmol/L seeretin group, 5 nmol/L secretin with somatostatin at 100 nmol/L of 10 nmol/L or 1 nmol/L groups, 0.： 3 nmol/L 8Br-cAMP group, 0.3 nmol/L 8Br-cAMP with 100 nmol/L somatostatin group, 1umol/L acetylcholine group, 1umol/L acetylcholine with 100 nmol/L somatostatin group, 5 nmol/L secretin with omeprazole at 10^-5 mol/L or 10^-6 mol/L or 10^-7 mol/L groups, 1 umol/L acetylcholine with omeprazole at 10^-5 mol/L or 10^-6mol/L or 10^-7 mol/L groups. Groups were compared by ANOVA, P〈0. 05 was considered statistically significant. Results The resting membrane voltage of rat RPA was -（40±0.8） mV, and when depolarization to ＋10 mV, Iks of control group was （420.0±3.2） pA. After treated with 5 umol/L or 20 umol/L 293B, Iks of RPA decreased to （60.4±4.2）% and （30.2±3.1）%（F=6.87, P〈0.05） of control group. Stimulated with 5 nmol/L secretin, Iks increased to （823.0± 2. 2） pA, and after adding somatostatin at 100 nmol/L or 10 nmol/L or 1 nmol/L, Iks decreased to （510. 0±3.2） pA, （584.0±2.8） pA and （789.0±6.9） pA respectively（F=5. 67,P〈0.05）, after adding omeprazole at 10^-5mol/L or 10^-6mol/L or 10^-7mol/L, the peak of Iks was （806.5±3.6） pA, （814.8± 3.2） pA and （816.3±2.9） pA （P〉0.05）. After stimulated with 1 umol/L acetylcholine, the peak value of Iks was （966.0±3.2） pA, and after adding omeprazole at 10^-5 mol/L or 10^-6 mol/L or 10^-7 mol/ L, the peak of Iks was （956.3±10.3） pA, （957.5±8.6） pA and （960.0±8.4） pA （P〉0.05）. Conclusion Somatostatin can inhibit Iks opening, and there is no significant inhibition of PPI on this channel.