Influence of sodium salts of saturated medium chain length (C6, C9, C10 and C12) dicarboxylic acids on the uterine horn of rat in vitro

The influence of the sodium salt of some dicarboxylic acids (adipic acid, C6; azelaic acid, C9; sebacic acid, C10; dodecandioic acid, C12) on both spontaneous and evoked activity of uterine horn of rats has been studied in vitro. Spontaneous activity of uterine muscle was inhibited by dicarboxylic salts (DS) causing the total abolition of mechanical events at concentrations of 64 x 10(-3) M-C6, 40 x 10(-3) M-C9, 32 x 10(-3) M-C10 and 24 x 10(-3) M-C12. Dicarboxylic salts antagonized the maximal isometric contraction of the uterine horn induced by administration of acetylcholine, oxytocin or prostaglandins (PGF2 alpha). The amount of antagonism was dependent upon the concentration of DS used. Dicarboxylic salt showed an aspecific inhibitory effect on the uterine horn which progressively increased with their chain length (C12 greater than C10 greater than C9 greater than C6). The results suggested that the inhibitory effects of DS on smooth muscle could be due to a cellular membrane hyperpolarization.