[Effect of doxofylline on calcium-activated potassium channels in human peripheral blood eosinophils in asthma].
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).


CONCLUSIONS
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.
Zhou
Bin
B
Department of Respiratory Medicine, Nanfang Hospital, Nanfang Medical University, Guangzhou 510515, China.
Cai
Shao-xi
SX
Zou
Fei
F
Cai
Chun-qing
CQ
Zhao
Hai-jin
HJ
D000293:Adolescent; D000328:Adult; D001249:Asthma / Q000097:blood / Q000378:metabolism*; D004804:Eosinophils / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D018408:Patch-Clamp Techniques; D024681:Potassium Channels, Calcium-Activated / Q000187:drug effects* / Q000378:metabolism; D013806:Theophylline / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D055815:Young Adult
D024681:Potassium Channels, Calcium-Activated; D013806:Theophylline; C029797:doxofylline