Maxi-K+ channel beta1 expression in sleep apnea patients and its modulation by CPAP treatment.

Background: Maxi-K(+) channels play a major vasodilator role in the regulation of arterial tone. Hypoxia downregulates the expression of the maxi-K(+) channel beta1-subunit in rat and human arterial myocytes, thus facilitating vasoconstriction. We have investigated the relationships among hypoxemia, arterial pressure, and the expression of the beta1-subunit in patients with severe obstructive sleep apnea-hypopnea syndrome (SAHS), a highly prevalent condition that predisposes to hypertension.