Takemura H, Ohshika H
J Dent Res. 1985 Jun;64(6):881-5. doi: 10.1177/00220345850640060401.
The role of calcium in the potentiation of amylase release by the alpha-adrenergic agonist methoxamine (MTX) was examined using dispersed rat parotid acinar cells. The stimulatory effect of MTX (10 microM) on the beta-adrenergic agonist isoproterenol (ISP, 1 microM)-induced amylase release was blocked by the alpha-adrenergic antagonist phentolamine (10 microM). In Ca-free (1 mM EGTA) medium, the increment of amylase release by MTX in normal medium was decreased by about 70%, but MTX still potentiated ISP-induced amylase release. MTX did not affect the cyclic AMP accumulation activated by ISP in either normal or Ca-free medium. MTX enhanced the ISP-stimulated uptake and efflux of 45Ca2+. These results suggest that both extracellular Ca2+ and intracellular stored Ca2+ may play an important role in the potentiation of amylase release from rat parotid acinar cells.
利用大鼠腮腺腺泡分散细胞，研究了钙在α-肾上腺素能激动剂甲氧明（MTX）增强淀粉酶释放过程中的作用。α-肾上腺素能拮抗剂酚妥拉明（10 μM）可阻断MTX（10 μM）对β-肾上腺素能激动剂异丙肾上腺素（ISP，1 μM）诱导的淀粉酶释放的刺激作用。在无钙（1 mM EGTA）培养基中，MTX在正常培养基中引起的淀粉酶释放增量降低了约70%，但MTX仍能增强ISP诱导的淀粉酶释放。MTX在正常或无钙培养基中均不影响ISP激活的环磷酸腺苷积累。MTX增强了ISP刺激的45Ca2+摄取和外流。这些结果表明，细胞外Ca2+和细胞内储存的Ca2+在增强大鼠腮腺腺泡细胞淀粉酶释放过程中可能都起重要作用。
