Objective: To study the effects of doxofylline on calcium-activated potassium (K(Ca)) channels of human peripheral blood eosinophils in asthma.
Methods: Peripheral blood eosinophils from patients with asthma were isolated and divided equally into two groups, a control group and a doxofylline incubated group. The data were recorded using cell-attached configuration of patch-clamp technique and the kinetic changes of K(Ca) channels activated by 0.2 micromol/L platelet activating factor (PAF) were compared.
Results: As compared with the control group, the open probability of the K(Ca) channels decreased from 0.135 +/- 0.021 to 0.044 +/- 0.018, the open time from (5.75 +/- 0.40) ms to (2.39 +/- 0.13) ms, while the close time increased from (2.17 +/- 0.50) ms to (23.73 +/- 2.50) ms in the doxofylline incubated group. The differences were significant between the two groups (all P < 0.05).
Conclusion: Doxofylline could decrease the open probability of the channels as a result of both the shortening of open period and the prolongation of close time.