EFFECT OF VARIATION IN ENDOGENOUS LEVELS OF ASCORBIC ACID ON THE in vitro IMMUNOLOGICAL RELEASE OF HISTAMINE AND SLOW REACTING SUBSTANCE OF ANAPHYLAXIS FROM ACTIVELY SENSITIZED GUINEA‐PIG LUNG FRAGMENTS

Abstract

The in vitro immunological release of histamine and slow reacting substance of anaphylaxis (SRS‐A) from actively sensitized guinea‐pig lung fragments was greatly reduced when the animals were maintained on an ascorbic acid‐deficient diet. Excessive dietary levels of ascorbic acid did not increase mediator release above normal levels. Restoration of ascorbic acid in the diet of scorbutic guinea‐pigs restored in vitro immunological histamine to normal levels. Variation in dietary levels of ascorbic acid had no effect on lung histamine content. The lung ascorbic acid content was proportional to the dietary intake. Approximately 60% of the total lung ascorbic acid was removed by the process of chopping and washing of the tissue. This relationship was independent of dietary intake. The results indicate that the immunological release of mediators of inflammation from guinea‐pig lung is dependent on adequate endogenous levels of ascorbic acid.

Non-specific Hyperreactivity to Pharmacological Stimuli in Tracheal and Lung Parenchymal Strips of Actively Sensitized Guinea-pigs

“…Thus, Krell et al(1976), Brink et a1 (1981), Saad & Burka (1983), Turner et al (1983) and Mansour & Daniel (1987) found no increase of responsiveness or sensitivity to agonists in sensitized tissues which is in contrast with the results from the present study. This discrepancy may be explicable in a number of ways such as the different animal species or strain used, the sensitization procedure (differences in the antigen and coadjuvant used, route of administration, time elapsed between sensitization and death of the animal, resensitization, challenge with antigen before testing the agonists), the additional supply of ascorbic acid in the diet of animals (Hitchcock 1980), the tissue preparation (type of strip mounted in the organ bath, presence or absence of intact epithelium, size of loading tension imposed to the tissue), and the type of recording (isometric vs isotonic, etc.) Notwithstanding, other authors The characteristics of the hyperresponsiveness observed in the present study closely resemble those reported for the reserpine-induced supersensitivity in rabbit aorta (Kalsner 1974) which has been associated with an enhanced ability of the tissue to retain and utilize calcium (Carrier & Hester 1976;Krishnamurty & Mukherjee 1981).…”

“…The control group was subjected to the same protocol but received only saline. The guinea-pigs were transported from the animal house to the laboratory at least two weeks before entering the sensitization or sham procedures, kept in individual cages under controlled conditions of light and temperature and with supplementary amount of ascorbic acid included in their diet, according to Hitchcock (1980), until killed.…”

Sources of Calcium for the Contraction Induced by Various Agonists in Trachealis Muscle from Normal and Sensitized Guinea Pigs

“…These diverging results may be attributed to differences in the experimental conditions, which are not uniform throughout the literature. Thus, the gender [20], the imm unization regimen [21] or the additional supply of ascorbic acid in the diet [8] may influence the re sponsiveness of the guinea pig airways. The discrepancies may be attributed, among other reasons, to these factors.…”

“…The con trol group was subjected to the same protocol but re ceived only saline. The guinea pigs were transported from the animal house to the laboratory at least 2 weeks before entering the sensitization or sham procedures, kept in individual cages under con trolled conditions of light and temperature and with a supplementary amount of ascorbic acid included in their diet [8] until sacrifice.…”

Effect of serotonin and calcium in normal and sensitized guinea pig isolated trachea

“…The normal group was subjected to the same protocol but the animals did not receive the antigen. The guinea pigs received a supplementary amount of ascorbic acid in their diet until sacrifice (Hitchcock, 1980). This sensitization procedure generates immunoglobulin GI (IgG,) as the major homocytotrophic antibody mediating the immediate hypersensitivity response in this species (Regal, 1984).…”