Similar Enhancement of BKCa Channel Function Despite Different Aerobic Exercise Frequency in Aging Cerebrovascular Myocytes.

Aerobic exercise showed beneficial influence on cardiovascular systems in aging, and mechanisms underlying vascular adaption remain unclear. Large-conductance Ca²⁺-activated K⁺ (BK_Ca) channels play critical roles in regulating cellular excitability and vascular tone. This study determined the effects of aerobic exercise on aging-associated functional changes in BK_Ca channels in cerebrovascular myocytes, Male Wistar rats aged 20-22 months were randomly assigned to sedentary (O-SED), low training frequency (O-EXL), and high training frequency group (O-EXH). Young rats were used as control. Compared to young rats, whole-cell BK_Ca current was decreased, and amplitude of spontaneous transient outward currents were reduced. The open probability and Ca²⁺/voltage sensitivity of single BK_Ca channel were declined in O-SED, accompanied with a reduction of tamoxifen-induced BK_Ca activation; the mean open time of BK_Ca channels was shortened whereas close time was prolonged. Aerobic exercise training markedly alleviated the aging-associated decline independent of training frequency. Exercise three times rather than five times weekly may be a time and cost-saving training volume required to offer beneficial effects to offset the functional declines of BK_Ca during aging. [ABSTRACT FROM AUTHOR]