Reaction of Bronchial Smooth Muscle in Sensitized Guinea Pigs on a Vitamin C Deficient Diet

Abstract

In a previous communication 1 we gave experimental evidence for the conclusion that removal of vitamin C from the diet of virgin female guinea pigs causes a loss of uterine smooth muscle reactivity to antigens and smooth muscle stimulants. This paper records similar observations on the effect of this dietary deficiency on the sensitized smooth muscle of the bronchi to horse serum, which calls attention to a lack of parallelism existing between the smooth muscle responses in these 2 different regions.

Virgin female guinea pigs weighing 250 to 350 gm. were fed for about 4 weeks on a diet of rolled oats and evaporated milk, a little bran being added to prevent possible intestinal obstruction from the hard fecal masses produced by the oats and milk. When the animals had been on this diet for about a week, they were sensitized by the intraperitoneal injection of 1 cc. horse serum. Some time between the second and third weeks the guinea pigs were sacrificed and simultaneous observations made on the smooth muscle reactivity of the bronchi and uterus of the same animal. The bronchiolar muscle reactions to horse serum were studied by the bronchial perfusion of the isolated, sensitized lung, 2 whereas the uterine segments were suspended in warmed Locke's solution.

Preliminary results support the conclusion that there is a lack of parallelism in the reactivity of the bronchial and uterine smooth muscle in sensitized animals on a vitamin C deficient diet. Whereas the uterine strips of such animals fail to respond both to antigen and smooth muscle stimulants, histamine, pituitary and barium, the introduction of horse serum and these pharmacologic agents into the bronchial tree cause a marked bronchoconstriction as evidenced by a reduction in the outflow of the perfusion fluid through the lung.