THE INFLUENCE OF BARBITURIC ACID, OF SOME BENZYL DERIVATIVES AND OF THE pH OF FLUIDS ON THE TONUS AND RHYTHMIC MOVEMENTS OF EXCISED SEGMENTS OF INTESTINE, UTERUS AND URETERS

¹ From the Department of Pharmacology, Washington University, School of Medicine, St. Louis, Missouri

1. All barbituric acid derivatives tested caused loss of tonus of the excised strips of intestine, uterus and ureters.

2. Sodium benzyl succinate and sodium dibenzyl phosphate although possessing some tonus relaxing properties are not as effective as the barbituric acid derivatives.

3. Change in pH of the fluid bathing the tissue is an important factor in the response of the tissue to drugs and must be considered in studying the action of drugs upon all excised strips of tissue.

4. Decreased pH of the fluid bathing the strips of intestine, uterus and ureters causes a lowered tonus and may cause it to disappear entirely. Increasing the pH results in heightened tonus of these same tissues.