Kadlec O, Radomirov R
Naunyn Schmiedebergs Arch Pharmacol. 1975;288(4):335-43. doi: 10.1007/BF00501280.
Responses of the longitudinal and circular smooth muscle of the guinea-pig caecum were studied in media with different concentrations of extracellular calcium. A sucrose-gap method was used to record the electrical and mechanical parameters of smooth muscle activity. In the longitudinal smooth muscle no difference in the action of PGF2alpha and PGE1 was seen at low (0.8 mM), Normal (2.5 mM) or high (7.5 mM) concentrations of Ca2+. Both PG's stimulated the longitudinal strip and the action of acetylcholine at normal Ca2+ concentration was slightly inhibited immediately after the superfusion with the PG's and augmented thereafter. In the circular strip no significant difference between the stimulatory effect of PGF2alpha, and PGE1 in low and high Ca2+ solution was found. However at 2.5 mM Ca2+ PGF2alpha evoked much greater stimulation of the circular strip than did PGE1. After the end of the superfusion with either PG the effect of acetylcholine was inhibited by either PG at low Ca2+ level and potentiated at high Ca2+ level the effect of acetylcholine was inhibited by PGE1 but not by PGF2alpha. Thus, the effects of PGF2alpha and PGE1 on the circular smooth muscle differed from each other in their dependence on the concentration of extracellular calcium.
在含有不同浓度细胞外钙的培养基中，研究了豚鼠盲肠纵行平滑肌和环行平滑肌的反应。采用蔗糖间隙法记录平滑肌活动的电参数和机械参数。在低（0.8 mM）、正常（2.5 mM）或高（7.5 mM）浓度的Ca2+条件下，PGF2α和PGE1对纵行平滑肌的作用未见差异。两种前列腺素均刺激纵行肌条，在正常Ca2+浓度下，用前列腺素灌流后，乙酰胆碱的作用立即略有抑制，随后增强。在环行肌条中，在低钙和高钙溶液中，PGF2α和PGE1的刺激作用无显著差异。然而，在2.5 mM Ca2+时，PGF2α对环行肌条的刺激作用比PGE1大得多。用任何一种前列腺素灌流结束后，在低钙水平时，乙酰胆碱的作用被任何一种前列腺素抑制，在高钙水平时则增强；乙酰胆碱的作用被PGE1抑制，但不被PGF2α抑制。因此，PGF2α和PGE1对环行平滑肌的作用在对细胞外钙浓度的依赖性方面彼此不同。
