Vascular motor reactivity and the expression of large-conductance calcium-activated potassium channels β1 in obstructive sleep apnea-hypopnea syndrome patients
XIAO Shu-ping
MA Ying-wen
ZHU Hai-ying
SUN Hong-yu
Abstract：Objective To evaluate cerebral vasomotor reactivity and to investigate the expression changs of large-conductance Ca2+-activated k + channels β1(BKCaβ1)in patients with obstructive sleep apnea-hypopnea syndrome(OSAHS).Methods Cerebrovascular reactivity was calculated by TCD-CO2 test(hypercapnia was induced by breath-holding and hypocapnia by hyperventilation)and squatting-to-tilt test; the change of BKCaβ1 in peripheral blood leukocytes was explored by reverse transcriptase-polymerase chain reaction(RT-PCR). Results Compared with healthy controls,vascular motor reactivity(VMR)decreased significantly in the severe and moderate OSAHS(P ＜ 0.05).The time from supine-to-tih position for the mean blood pressure and the cerebral blood flow velocity(CBFV)to return to ＞ 90％ of baseline levels was longer in the moderate and severe OSAHS(all P ＜ 0.05 );Bp and CBFV at tilt position decreased in the moderate and severe OSAHS(P ＜0.05).The expression of BKCaβ1mRNA in the moderate and severe OSAHS markedly reduced compared with that in healthy controls(0.63 ± 0.38and 0.48 ±0.29 vs 1.13 ±0.41,P ＜0.05).The extent of VMR was correlated positively to the level of BKCa β1mRNA.Conclusions Cerebral vascular motor reactivity is attenuated in OSAHS patient,especially in the moderate and severe groups.OSAHS down-regulates BKCaβ1 mRNA in peripheral blood leukocytes.BKCaβ1 can contribute to vascular dysfunction in severe OSAHS patient.
Keywords：Sleep apneaobstructiveLarge-conductance calcium-activated potassium channelsVascular motor reactivity
Publication Date：2012-01-01
Online Publishing Date：2026-09-14(First online date of this platform, not the publication date of the document)