The effect of sodium on the biological activity of slow-reacting substances.
Sodium can inhibit the specific binding of leukotriene D4 (LTD4) to its receptors. The effects of sodium on the biological activity of slow-reacting substance (SRS) which contains LTD4 are studied here. SRS was produced in leukocytes from seven normal donors. Its activity was bioassayed by guinea pig ileum contraction in an organ bath containing Tyrode's solution with 0.11 M NaCl. With higher concentrations of NaCl, the SRS-induced ileum contraction increased 45% at 0.14 M of NaCl (P less than 0.02), and 55% at 0.18 M NaCl (P less than 0.02). When NaCl concentration was increased to 0.21 M, the contractibility only increased 18% from the baseline (0.11 M NaCl), evidencing no statistical difference. The direct effect of changing NaCl solution from 0.11 to 0.21 M was to induce a significant ileum contraction with dose-related pattern.
Tsai
J J
JJ
Wang
S R
SR
D000818:Animals; D012898:Autacoids / Q000502:physiology*; D006168:Guinea Pigs; D006801:Humans; D007082:Ileum / Q000187:drug effects; D066298:In Vitro Techniques; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D009994:Osmolar Concentration; D012964:Sodium / Q000494:pharmacology*
D012898:Autacoids; D012964:Sodium