Abstract
The effect of thymol on the electrical and mechanical activities of various regions of the guinea pig alimentary canal were investigated.
1) In the stomach, thymol (<0.5mM) suppressed the generation of action potential and slow potential changes without any marked change in membrane potential and membrane resistance. Increased concentrations of thymol (>0.5 mM) reduced membrane potential and membrane resistance.
2) In the ileum and rectum, thymol (<1mM) suppressed spike activity only without any marked change in the membrane potential. However, 1 mm thymol suppressed spike generation, hyperpolarized the membrane and decreased membrane resistance.
3) Thymol (0.5 mM) suppressed spontaneous mechanical responses which appeared in the various regions of the alimentary canal. There was no contracture except in stomach muscle.
4) Although the membrane was completely depolarized, thymol (>1 mM) suppressed the generation of phasic and tonic responses of the K-induced contracture evoked in the various regions of the alimentary canal.
5) Topical differences of the effects of thymol on the various regions of alimentary canal were discussed in relation to the roles of Ca in the cells and the obtained results were compared to those observed in treatment with caffeine.
