Study of TRH in the postganglionic sypnasis of the isolated human vas deferens

Cummulative dose-response curves to l-noradrenaline and in presence of different concentrations of TRH (10(-3), 10(-4), 10(-5), 10(-6), 10(-7), and 10(-8) M) were investigated. 25 segments of vas deferens (escrotal tract) were obtained from different surgical patients of urological disorders. At the lower concentration (greater than 10(-7) M), we can not appreciate any influence of TRH on the l-noradrenaline response. Nevertheless there was a reduction of response to l-noradrenaline, with displacement of the curves to the right side, for the high concentrations, and a proportional ratio to the concentration to TRH.