不同频率有氧运动对大鼠离体肠系膜上动脉反应性的影响

Objective: To study the effect of aerobic exercise in different frequencies on the vascular reactivity of the superior mesenteric arteries and to explore the possible mechanisms. Method: 18 male Wistar rats (8w) were randomly divided into three groups: sedentary control group (SED), low frequency training group (3days per week, EX-3d/w), high frequency training group (5days per week, EX-5d/w). The contractile responsiveness of the superior mesenteric arteries of all groups to norepinephrine (NE), angiotensinⅡ(AngⅡ), nonspecific K+ channel blocker tetraethylammonium (TEA), large conductance Ca2+-activated K+ channel (BKCa ) blocker Iberiotoxin (IbTX) and BKCa opener NS1619 were examined. Results: NE (10-9~3×10-5M) caused a significantly increase of vascular tone in a concentration-dependent manner in all groups, while the increase amplitude was less in EX-5d/w group than in EX-3d/w group than in the SED group. AngⅡ(3×10-7M) could produce a sustained tension increase in all three groups, which was more significant in exercise groups than in SED group. TEA (3×10-3M) and IbTX (3×10-8M) could induce arterial tension increase, too. The maximal increase of vascular tone was EX-5d/w > EX-3d/w > SED. The dilation elicited by NS1619 (10-9~10-6M) on NE-induced contraction was more significant in exercise groups (EX-3d/w and EX-5d/w) than in SED group. Conclusion: aerobic exercise training can change the vascular reactivity in superior mesenteric arteries in a frequency-dependent manner, in which BKCa channels of the vascular smooth muscle cells play an important role.