The bronchopulmonary pharmacology of SK&F 104353 in anesthetized guinea pigs: demonstration of potent and selective antagonism of responses to peptidoleukotrienes

J Pharmacol Exp Ther. 1989 May;249(2):430-7.

Abstract

The bronchopulmonary pharmacology of SK&F 104353 [2(S)-hydroxy-3(R)-[2(2-carboxyethyl)thio]-3[2-(8- phenyloctyl)phenyl]-propanoic acid], a potent and selective leukotriene (LT) receptor antagonist in vitro, was assessed in anesthetized, spontaneously breathing guinea pigs. Aerosol administration of SK&F 104353 (5-2000 micrograms/ml x 100 breaths) reduced in a concentration-dependent manner the response to a standard LTD4 challenge (4.33 micrograms/ml x 5 breaths) given 30 min later. Inhalation of a 2000 micrograms/ml solution abolished LTD4-induced bronchoconstriction for at least 2 hr. The i.v. administration of SK&F 104353 10 min before challenge antagonized LTD4-induced bronchoconstriction with an ID50 of 0.55 mumol/kg (0.25 mg/kg). Substantial antagonism of LTD4-induced bronchospasm was observed for at least 60 min after i.v. administration of 5 mumol/kg of SK&F 104353. Infusion of SK&F 104353 at various rates revealed that a steady-state plasma concentration of 0.125 microM (0.06 micrograms/ml) reduced LTD4-induced bronchoconstriction by 60%. In addition to preventing the response to LTD4, i.v. administered SK&F 104353 (10 mumol/kg) rapidly and completely reversed ongoing LTD4-induced bronchoconstriction. SK&F 104353 also was effective when given intraduodenally 1 hr before LTD4 challenge, although the ID50 (32 mumol/kg) was 60-fold greater than the i.v. ID50. Given intragastrically, 100 mumol/kg of SK&F 104353 abolished the response to LTD4 for 1 hr, and reduced the response for 6 hr. SK&F 104353 (20 mumol/kg i.v.) had no effect on the bronchoconstriction induced by aerosolized acetylcholine, histamine or U-44069, but did antagonize the response to LTC4. SK&F 104353 alone did not produce bronchoconstriction when administered by any route or dose.(ABSTRACT TRUNCATED AT 250 WORDS)

MeSH terms

  • Aerosols
  • Anesthesia
  • Animals
  • Biological Availability
  • Blood Proteins / metabolism
  • Bronchi / drug effects*
  • Dicarboxylic Acids / administration & dosage
  • Dicarboxylic Acids / blood
  • Dicarboxylic Acids / pharmacology*
  • Guinea Pigs
  • Injections, Intravenous
  • Male
  • Protein Binding
  • Receptors, Immunologic / drug effects
  • Receptors, Leukotriene
  • SRS-A / antagonists & inhibitors*

Substances

  • Aerosols
  • Blood Proteins
  • Dicarboxylic Acids
  • Receptors, Immunologic
  • Receptors, Leukotriene
  • SRS-A
  • pobilukast