Takemura H
Res Commun Chem Pathol Pharmacol. 1984 Aug;45(2):179-90.
The effect of the Ca ionophore A23187 on isoproterenol (ISP)-induced amylase release was investigated using isolated rat parotid acinar cells. A23187 increased amylase release in normal medium but this stimulated effect of A23187 was abolished in Ca-free medium. ISP-induced amylase release was inhibited by A23187 in Ca-free medium but not in normal medium. A23187 did not affect basal levels of cyclic AMP in normal medium or Ca-free medium but reduced the accumulation of cyclic AMP stimulated by ISP in both mediums. Both NaF- and ISP-stimulated activities of adenylate cyclase were reduced in washed membrane fraction prepared from A23187-treated slices of parotid glands. 45Ca2+ uptake stimulated by A23187 markedly increased, reached maximum at 10-20 min and then declined immediately. These results suggest that A23187 decreases the accumulation of cyclic AMP stimulated by ISP and results in an inhibition of ISP-induced amylase release in the absence of extracellular Ca2+, whereas a marked influx of Ca2+ stimulated by A23187 may possibly compensate the decrement of amylase release in the presence of extracellular Ca2+.
利用分离的大鼠腮腺腺泡细胞，研究了钙离子载体A23187对异丙肾上腺素（ISP）诱导的淀粉酶释放的影响。A23187在正常培养基中增加了淀粉酶的释放，但在无钙培养基中，A23187的这种刺激作用被消除。在无钙培养基中，A23187抑制了ISP诱导的淀粉酶释放，但在正常培养基中则没有。A23187不影响正常培养基或无钙培养基中环磷酸腺苷（cAMP）的基础水平，但降低了两种培养基中ISP刺激的cAMP积累。在用A23187处理的腮腺切片制备的洗涤膜组分中，氟化钠（NaF）和ISP刺激的腺苷酸环化酶活性均降低。A23187刺激的45Ca2+摄取显著增加，在10 - 20分钟时达到最大值，然后立即下降。这些结果表明，在没有细胞外Ca2+的情况下，A23187减少了ISP刺激的cAMP积累，并导致对ISP诱导的淀粉酶释放的抑制，而A23187刺激的显著Ca2+内流可能在存在细胞外Ca2+的情况下补偿淀粉酶释放的减少。
