Effect of cooling on contraction of sensitized guinea-pig trachea

ABSTRACT

The effect of cooling on contractility of ovalbumin sensitized guinea pig trachea was elucidated and the possible mechanisms underlying the effects of cooling on contractility induced by histamine, 5-HT and ovalbumin were investigated. Cooling of temperature from 37C to 25C is associated with significant increase in tracheal contractions to exogenously administered 5-1T, histamine and ovalbumin. Verapamil incubation [10 muM] produced significant depression of the contractile responses at 25C but not at 37C. These results demonstrated that the cooling induced contractile augmentation of the sensitized guinea-pig trachea to ovalbumin is due to 5-HT and histamine. The mechanisms of this augmentation may involve the increased opening of calcium channels in the membranes to allow calcium influx or the mobilization of calcium from intracellular calcium stores