Influence of α-Adrenoceptor Mediated Vasoconstriction on Spontaneously Hypertensive Rats after Exercise Training

摘要

This study aims to examine the effects of aerobic exercises for 8 weeks on vascular contraction with a-adrenaline acceptor in SHR (Spontaneously Hypertensive Rats). The rats of 8 weeks with hypertension (SHR) having the weight of 155 ～ 165g were aerobic-exercised with using treadmill for 5 days a week through 8 weeks (20m/min). After 8 weeks, chest artery is extracted, suspended into organ bath and changes of isotonia tension are recorded on vital records. The piece of extracted chest artery showed density depending contraction by norepinephrine and its sensitivity to Emax and norepinephrine was significantly reduced after aerobic exercise for 8 weeks. Contraction reaction was accelerated in both groups after eliminating endothelium cell, but when L-NNA was input in the state with endothelium cell, contraction reaction by norepinephrine was increased in exercise group and its aspect was similar to the contraction by norepinephrine in the state eliminating endothelium cell. Relaxation by acetylcholine was significantly increased in exercise group, but there was no difference in relaxation by sodium nitroprusside. In conclusion, vascular endothelium cell isolates niotric oxide and reduces contraction reaction of blood vessel with a exercise group, but there was no difference in relaxation by sodium nitroprusside.