[Effect of tiemonium iodide on colonic motility in dogs]

Effects of tiemonium iodide (tiemonium, 20 micrograms/kg), mepenzolate bromide (mepenzolate, 20 micrograms/kg), butylscopolamine bromide (butylscopolamine, 50 micrograms/kg) and atropine sulfate (atropine, 10 micrograms/kg) on the colonic motility in dogs were evaluated using a balloon method. The frequency of the wave motion was analyzed by fast Fourier transform, and the power spectra were obtained. The value of the first term of the power spectrum is regarded as an indication of the colonic tonus. Inhibitory effects of tiemonium on both the normal proximal colonic motility and the accelerating motility induced by neostigmine metylsulfate (neostigmine, 50 micrograms/kg) were equal to those of butylscopolamine. In the case of distal colonic motility, tiemonium showed potent mepenzolate-like inhibition. When the drugs were injected into the veins after administration of PGF2 alpha (10 micrograms/kg), all of the drugs depressed the colonic constriction induced by PGF2 alpha. The colonic motility was not restored by the administration of tiemonium or mepenzolate before the injection of PGF2 alpha, but such an effect was not observed in the case of butylscopolamine and atropine. It is suggested that tiemonium shows an extensive inhibition on the colonic motility in the mode of mepenzolate-like action and by some additional mechanism.