[Effect of neurotensin and substance P on the active state of the gastric smooth muscles].

Activating effect of neurotensin applied to muscle strips taken from fundal and antral portions of the guinea pig stomach was found to be due to depolarization of the muscle cells membrane and activation of the electrically controlled calcium channels. Activating effect of substance P seems to be associated with the activation of the chemo-controlled calcium channels as the contraction following the substance P application develops with no apparent changes in the membrane potential. Substance P increases the amplitude of the potassium contracture tonic component.