Adenosine modulates vasomotor tone in outer medullary descending vasa recta of the rat.
Adenosine modulates vasomotor tone in outer medullary descending vasa recta of the rat.
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腺苷调节大鼠外髓降血管直肠的血管舒缩张力。
DOI：
10.1172/jci118764
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Pallone,TL
中科院分区：
文献类型：
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作者：
Silldorff,EP;Kreisberg,MS;Pallone,TL
腺苷是在低氧条件下在肾髓质内产生的，已知在肾皮质内诱导净血管收缩，同时增加髓质血流量和氧合。为验证腺苷对大鼠延髓降支直肠外血管(OMDVR)血管收缩的调节作用，我们观察了腺苷、腺苷A1和A2受体亚型激动剂对体外灌流对照和预缩窄大鼠OMDVR的影响。腺苷对血管紧张素II(Ang II，10(-9)M)的收缩作用呈浓度依赖性减弱(EC50=2.0×10(-7)M，P<0.05)。同样，腺苷A2激动剂(CGS-21680，10(-7)M)，而不是腺苷A1激动剂(环己基腺苷，10(-6)M)，可减弱血管紧张素II诱导的血管收缩。在对照条件下，灌胃给予腺苷(10(-12)~10(-5)M)可引起双相反应。此外，环己基腺苷(10(-6)M)可引起血管收缩，而CGS-21680(10(-6)M)对未处理的血管无作用。最后，激活血管紧张素Ⅱ受体对腺苷Al受体介导的血管收缩没有影响。这些数据表明，OMDVR同时具有A1和A2腺苷受体，它们分别介导收缩和扩张。我们得出结论，腺苷是OMDVR血管舒缩张力的有效调节剂，其净作用依赖于局部浓度。
Adenosine is generated within the renal medulla under hypoxic conditions and is known to induce net vasoconstriction within the renal cortex while increasing medullary blood flow and oxygenation. To test the hypothesis that vasoconstriction of outer medullary descending vasa recta (OMDVR) is modulated by adenosine, we examined the effects of adenosine and adenosine Al and A2 receptor subtype agonists on in vitro perfused control and preconstricted rat OMDVR. Constriction with angiotensin II (ANG II, 10(-9) M) was attenuated by adenosine in a concentration-dependent manner (EC50 = 2.0 x 10(-7)M, P < 0.05). Similarly, an adenosine A2 agonist (CGS-21680, 10(-7) M), but not an adenosine Al agonist (cyclohexyladenosine, 10(-6) M), attenuated ANG II-induced vasoconstriction. Under control conditions, ablumenal application of adenosine (10(-12) to 10(-5) M) elicited a biphasic response. Additionally, cyclohexyladenosine (10(-6) M) caused vasoconstriction and CGS-21680 (10(-6) M) had no effect on untreated vessels. Finally, an influence of ANG II receptor stimulation on adenosine Al receptor-mediated vasoconstriction could not be shown. These data suggest that OMDVR possess both Al and A2 adenosine receptors and that they mediate constriction and dilatation, respectively. We conclude that adenosine is a potent modulator of OMDVR vasomotor tone and that its net effect is dependent upon local concentrations.