腺苷对离体血管平滑肌的舒张作用。
Adenosine relaxation of isolated vascular smooth muscle.
作者信息
Herlihy J T, Bockman E L, Berne R M, Rubio R
出版信息
Am J Physiol. 1976 May;230(5):1239-43. doi: 10.1152/ajplegacy.1976.230.5.1239.
Adenosine relaxed hog carotid media strips contracted with norepinephrine (NE) and potassium (K+). Adenosine (3 X 10(-6)M) was more effective in relaxing the NE contractures than those produced by K+. In both cases, adenosine's efficacy decreased with increasing concentrations of the stimulating agent. A high adenosine concentration (1 X 10(-3)M) was necessary to elicit relaxation of completely depolarized (124 mM K+) media strips and equimolar concentrations of aminophylline caused greater relaxation than did adenosine. Adenosine inhibited the Ca2+ dose-response curves of strips stimulated with 20 mM and 30 mM K+ and its effect was dependent on the Ca2+ concentration. Neither 1 X 10(-6)M nor 1 X 10(-4)M adenosine produced any change in the cAMP content of vascular strips. Only at high concentrations did adenosine increase the cAMP content of vascular strips, but the increase was signficantly more than that observed with the same dose of aminophylline. The present results are consistent with the possibility that adenosine relaxes vascular smooth muscle by directly altering Ca2+ permeability and/or membrane potential; they do not support a role for cAMP in the adenosine-induced relaxation of vascular smooth muscle.
腺苷可使由去甲肾上腺素（NE）和钾离子（K⁺）引起收缩的猪颈动脉中膜条舒张。腺苷（3×10⁻⁶M）对NE引起的收缩的舒张作用比对K⁺引起的收缩更有效。在这两种情况下，腺苷的效力均随刺激剂浓度的增加而降低。需要高浓度的腺苷（1×10⁻³M）才能使完全去极化（124 mM K⁺）的中膜条舒张，等摩尔浓度的氨茶碱比腺苷引起的舒张作用更强。腺苷可抑制由20 mM和30 mM K⁺刺激的中膜条的Ca²⁺剂量反应曲线，其作用取决于Ca²⁺浓度。1×10⁻⁶M和1×10⁻⁴M的腺苷均未使血管条的cAMP含量发生任何变化。只有在高浓度时，腺苷才会增加血管条的cAMP含量，但增加量明显高于相同剂量氨茶碱所观察到的增加量。目前的结果与腺苷通过直接改变Ca²⁺通透性和/或膜电位来舒张血管平滑肌的可能性一致；它们不支持cAMP在腺苷诱导的血管平滑肌舒张中起作用。
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