Differential effects of B(2) receptor antagonists upon bradykinin-stimulated phospholipase C and phospholipase D in guinea-pig cultured tracheal smooth muscle

S Pyne, N J Pyne

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21 Citations (Scopus)


Guinea-pig tracheal smooth muscle cells were isolated and maintained in culture for 14-21 days prior to the study of the effect of a selective bradykinin B1 agonist and B2 antagonists upon bradykinin-stimulated phospholipase C and D activities. Bradykinin-stimulated phospholipase C activity was determined by mass measurement of inositol (1,4,5)trisphosphate (Ins(1,4,5)P3) in unlabelled cells, whereas phospholipase D activity was assayed by the accumulation of [3H]-phosphatidylbutanol ([3H]-PtdBut) in [3H]-palmitate-labelled cells, which were stimulated in the presence of butan-1-o1 (0.3%, v/v). Bradykinin elicited the rapid and transient formation of Ins(1,4,5)P3, in a concentration-dependent manner (log EC50 = -7.55 +/- 0.1 M, N = 3). Bradykinin also rapidly activated the concentration-dependent (log EC50 = -8.3 +/- 0.4 M, n = 3) phospholipase D-catalysed accumulation of [3H]-PtdBut; the accumulation of [3H]-PtdBut was sustained. These effects were not inhibited by pretreatment of the cells with indomethacin (1 microM). The bradykinin B1 agonist, desArg9-bradykinin (1 microM) was without effect upon phospholipase C or phospholipase D activity. Bradykinin-stimulated (10 nM, EC40) Ins(1,4,5)P3 formation was inhibited by B2 receptor antagonists, D-Arg-[Hyp3,D-Phe7]-bradykinin (NPC 567) and D-Arg-[Hyp3,Thi5,8,D-Phe7]-bradykinin (NPC 349), with log IC50 values of -6.3 +/- 0.5 M and -6.3 +/- 0.4 M, respectively. However, bradykinin-stimulated (10 nM, EC100) [3H]-PtdBut accumulation was poorly inhibited and with low potency by each B2 receptor antagonist and bradykinin-stimulated phospholipase D activity persisted at concentrations of antagonist that completely blocked bradykinin-stimulated Ins(1,4,5)P3 formation (30 microM). These observations suggest that the activation of phospholipase C by bradykinin may be mediated through a bradykinin B2 receptor population, whereas bradykinin-stimulated phospholipase D may be activated via a distinct population of bradykinin receptors that do not appear to be either B1 or B2 receptor types, based upon pharmacological specificity. The mechanism of the activation of phospholipase D by bradykinin and the role of the putative B3 bradykinin receptor are discussed.
Original languageEnglish
Pages (from-to)477-481
Number of pages5
JournalBritish Journal of Pharmacology
Issue number1
Publication statusPublished - Sept 1993


  • animals
  • bradykinin
  • culture techniques
  • glycerophospholipids
  • guinea pigs
  • indomethacin
  • inosine triphosphate
  • male
  • muscle, smooth
  • palmitic acid
  • palmitic acids
  • phosphatidic acids
  • phospholipase D
  • receptors, bradykinin
  • trachea
  • type C phospholipases


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