Fast D, Tenenhouse A
Br J Pharmacol. 1976 Dec;58(4):605-12. doi: 10.1111/j.1476-5381.1976.tb08630.x.
1 The mechanism by which dibutyryl cyclic adenosine-3'-5'-monophosphate (dibutyryl cyclic AMP) potentiates the secretory effect of carbachol in rat exocrine pancreas was investigated. 2 Dibutyryl cyclic AMP potentiated the secretory effect of carbachol only at carbachol concentrations greater than or equal to 10(-7) mol/l; was independent of carbachol at concentrations greater than 10(-7) mol/l and was inversely proportional to extracellular [Ca2+]. 3 Carbachol increased and dibutyryl cyclic AMP reduced the rate of 45Ca efflux from the tissue. 4 A-23187 stimulated 3H-protein release in the presence of Ca2+ and this effect was potentiated by dibutyryl cyclic AMP; the degree of potentiation was inversely proportional to extracellular [Ca2+]. At 10(-3) mol/l [Ca2+] the potentiation occurred only at ionophore concentrations less than or equal to 10(-6) mol/litre. 5 These results support the hypothesis that dibutyryl cyclic AMP potentiates the effect of secretagogues in rat exocrine pancreas by maintaining an elevated intracellular calcium concentration. It does so by inhibiting Ca2+ efflux. The results also suggest that the limiting factor in carbachol-stimulated secretion, at all concentrations of carbachol, is intracellular [Ca2+].
1 研究了二丁酰环腺苷 - 3'-5'-单磷酸（二丁酰环磷酸腺苷）增强卡巴胆碱对大鼠外分泌胰腺分泌作用的机制。2 二丁酰环磷酸腺苷仅在卡巴胆碱浓度大于或等于10(-7)mol/L时增强其分泌作用；在浓度大于10(-7)mol/L时与卡巴胆碱无关，且与细胞外[Ca2+]呈反比。3 卡巴胆碱增加而二丁酰环磷酸腺苷降低组织中45Ca的流出率。4 A - 23187在有Ca2+存在时刺激3H - 蛋白质释放，且此作用被二丁酰环磷酸腺苷增强；增强程度与细胞外[Ca2+]呈反比。在[Ca2+]为10(-3)mol/L时，增强作用仅在离子载体浓度小于或等于10(-6)mol/L时出现。5 这些结果支持这样的假说，即二丁酰环磷酸腺苷通过维持细胞内钙浓度升高来增强大鼠外分泌胰腺中促分泌剂的作用。它通过抑制Ca2+流出做到这一点。结果还表明，在所有卡巴胆碱浓度下，卡巴胆碱刺激分泌的限制因素是细胞内[Ca2+]。
