Alterations of airway smooth muscle cell membrane by sensitization

Abstract

The sensitization of guinea pigs with ovalbumin and Bacillus pertussis vaccine caused an increase (P less than 0.001) in the resting membrane potential (Em) of airway smooth muscle (ASM) cells, from -61.3 +/- 0.5 mV (+/- SE) to -72.7 +/- 0.6 mV (+/- SE). One, two, and three weeks after resensitization of sensitized animals with ovalbumin, Em further increased (P less than 0.001) to -76.2 +/- 0.2 mV (+/- SE), -77.4 +/- 0.3 mV, and -78.1 +/- 0.5 mV, respectively. Similarly, both in vivo and in vitro passive sensitization caused an increase (P less than 0.001) in Em of ASM cells to -69.5 +/- 0.3 mV and -68.5 +/- 0.4 mV, respectively. ASM preparations isolated from rabbits showed a similar increase (P less than 0.001) in Em after passive in vitro sensitization with serum from ovalbumin-sensitized rabbits. An increase in the contribution of the electrogenic Na+-pump was found to be responsible for the observed changes in Em following both active and passive sensitization. The presence of diphenhydramine (anti-H1), methysergide, indomethacin, 5,8,11,14-eicosatetraenoic acid (ETYA), FPL 55712 (a leukotriene receptor blocker), phenoxybenzamine, and disodium cromoglycate (a stabilizing agent) during passive in vitro sensitization failed to prevent an increase in the Em of ASM cells. However, incubation of normal guinea pig and rabbit ASM preparations with heated serum (60 degrees C for 2 hours) from ovalbumin-sensitized guinea pigs or rabbits partially inhibited (in guinea pigs) or completely abolished (in rabbits) such an increase.(ABSTRACT TRUNCATED AT 250 WORDS)