Pharmacological characterizations of the in vitro anaphylactic contraction of the guinea-pig esophageal muscularis mucosae

Abstract

Characteristics of the antigen-induced contraction of the isolated esophageal muscularis mucosae of actively sensitized guinea-pigs to ovalbumin (OA) were examined in vitro, and they were compared with those of compound 48/80- or polymyxin B-induced contraction. OA, above 0.01 microgram/ml, produced a sustained contraction of the sensitized esophageal muscularis mucosae, the amplitude of which was about 80-100% of the maximum contraction induced by carbachol (10 microM), while compound 48/80 and polymyxin B (10-300 micrograms/ml) produced less potent contractions of the non-sensitized esophageal muscularis mucosae. Contractions to OA or compound 48/80, but not to polymyxin B, were diminished by their repetitive applications. The contractile responses to OA, compound 48/80 and polymyxin B depended on the external calcium concentrations, and were abolished in the calcium-free medium. Pretreatment with tetrodotoxin (0.3 microM), atropine (0.3 microM), diphenhydramine (30 microM) or DSCG (300 microM) did not modify any of these contractions, whereas BW755C (100 microM) and quercetin (10 microM) significantly inhibited them. Indomethacin (10 microM) largely prevented only the polymyxin B-induced contraction, while FPL55712 (10 microM) inhibited both contractions to OA and compound 48/80. These findings indicate that the OA-induced anaphylactic contraction of the esophageal muscularis mucosae taken from the OA-sensitized guinea-pig may be an indirect action via the stimulation of releases of some mast cell-derived spasmogens. The spasmogens may involve the lipoxygenase products of arachidonic acid in part, but not histamine, acetylcholine or the cyclooxygenase products.