[Changes of Ca2+ channel behaviors in bronchial smooth muscle cells of asthma guinea-pig model].

Objective: To investigate the relationship between the change of calcium channel behavior in bronchial smooth muscle cells (BSMCs) and the airway hyperresponsiveness in guinea-pigs with asthma.

Methods: The changes of calcium channel dynamics in BSMCs of 4 asthma guinea-pig models (22 cells) and 5 normal guinea-pigs (25 cells), and the inner peak calcium current in BSMCs of 5 asthma guinea-pig models (25 cells) and 6 normal guinea-pigs (24 cells) were determined by patch-clamp techniques.

Results: (1) The open time of calcium channel in BSMCs of asthma group was (1.70 +/- 0.40) ms, 2.32 times as much as that of control group (0.70 +/- 0.10) ms; the close time of calcium channel in BSMCs of asthma group (5.7 +/- 0.6) ms, was significantly shorter that that of control group (7.9 +/- 0.4) ms; The open probability in asthma group (0.40 +/- 0.10)% was significantly increased than that of control group (0.20 +/- 0.20)%, (P < 0.01); (2) The inner peak calcium current in BSMCs of asthma group was (-54 +/- 23) PA, 1.17 times as muth as that of control group (-25 +/- 8) PA, (P < 0.01).

Conclusion: The enhanced activity of calcium channel an BSMCs of asthma guinea-pig mudels may be one of the important factors responsible for the airway hyperresponsiveness.