Krothapalli R K, Duffy W B, Senekjian H O, Suki W N
J Clin Invest. 1983 Jul;72(1):287-94. doi: 10.1172/jci110968.
The effects of catecholamines on antidiuretic hormone ([Arg(8)]-vasopressin [AVP])-induced water absorption were evaluated in cortical collecting tubules isolated from the rabbit kidney and perfused in vitro. In the presence of AVP (100 muU/ml), net fluid volume absorption (J(v), nanoliters per minute per millimeter) was 1.14+/-0.12 and osmotic water permeability coefficient (P(f), X 10(-4) centimeters per second) was 217.3+/-39.9. The addition of the alpha-adrenergic agonist, phenylephrine (PE), in a concentration of 10(-6) M resulted in a significant decrease in J(v) and P(f) to 0.83+/-0.13 (P < 0.001) and 148.8+/-41.8 (P < 0.02), respectively. Increasing the concentration of PE to 10(-5) M resulted in a further decrease in J(v) and P(f) to 0.53+/-0.05 (P < 0.05 vs. PE 10(-6) M) and 88.5+/-9.0 (P 0.05 vs. PE 10(-6) M), respectively. In a separate group of tubules, in the presence of AVP (100 muU/ml) and PE (10(-5) M), J(v) and P(f) were 0.35+/-0.07 and 66.0+/-17.3, respectively. The addition of the alpha-adrenergic antagonist, phentolamine (PH), in a concentration of 10(-6) M resulted in a significant increase in J(v) to 1.07+/-0.19 (P < 0.001) and P(f) to 193.3+/-35.9 (P < 0.005). PH (10(-5) M) alone did not significantly affect J(v) and P(f) in the presence of AVP (100 muU/ml) nor in the presence of 8-bromo adenosine 3',5' cyclic monophosphate (8-BrcAMP). J(v) and P(f) were 1.20+/-0.21 and 174.0+/-25.8, respectively, in the presence of 8-BrcAMP (10(-4) M). We next examined the effect of the beta-adrenergic agonist, isoproterenol (ISO), on J(v) and P(f) in the presence of AVP. J(v) and P(f) were 1.04+/-0.10 and 202.6+/-17.2, respectively, in the presence of AVP (100 muU/ml) and 1.06+/-0.18 and 193.4+/-27.7, respectively, in the presence of AVP (10muU/ml). However, in the presence of AVP in a concentration of 2.5 muU/ml, J(v) was 0.60+/-0.07 and P(f) was 100.7+/-24.7. ISO (10(-6) and 10(-5) M) did not have any significant effect in the presence of the above maximal and submaximal concentrations of AVP. In the absence of AVP, control J(v) was 0.01+/-0.12 and P(f) was 4.6+/-11.0. The addition of ISO at 25 or 37 degrees C did not result in any significant change in J(v) or P(f). These studies indicate that alpha-adrenergic agonists directly inhibit AVP-mediated water absorption at the level of the tubule, an effect that can be blocked by a specific alpha-adrenergic antagonist. This effect appears to be exerted at the level of activation of adenylate cyclase since it is absent in the presence of cAMP. The beta-adrenergic agonists do not directly inhibit or enhance AVP-mediated water absorption at the level of the renal tubule.
在体外灌注的兔肾皮质集合管中，评估了儿茶酚胺对抗利尿激素（[精氨酸（8）] - 血管加压素[AVP]）诱导的水吸收的影响。在存在AVP（100 μU/ml）的情况下，净液体体积吸收（J(v)，每分钟每毫米纳升数）为1.14±0.12，渗透水渗透系数（P(f)，×10(-4)厘米每秒）为217.3±39.9。添加浓度为10(-6) M的α-肾上腺素能激动剂去氧肾上腺素（PE）导致J(v)和P(f)显著降低，分别降至0.83±0.13（P < 0.001）和148.8±41.8（P < 0.02）。将PE浓度增加到10(-5) M导致J(v)和P(f)进一步降低，分别降至0.53±0.05（与PE 10(-6) M相比，P < 0.05）和88.5±9.0（与PE 10(-6) M相比，P 0.05）。在另一组肾小管中，在存在AVP（100 μU/ml）和PE（10(-5) M）的情况下，J(v)和P(f)分别为0.35±0.07和66.0±17.3。添加浓度为10(-6) M的α-肾上腺素能拮抗剂酚妥拉明（PH）导致J(v)显著增加至1.07±0.19（P < 0.001），P(f)增加至193.3±35.9（P < 0.005）。单独的PH（10(-5) M）在存在AVP（100 μU/ml）时或在存在8-溴腺苷3',5'-环磷酸（8-BrcAMP）时对J(v)和P(f)没有显著影响。在存在8-BrcAMP（10(-4) M）时，J(v)和P(f)分别为1.20±0.21和174.0±25.8。接下来，我们研究了β-肾上腺素能激动剂异丙肾上腺素（ISO）在存在AVP时对J(v)和P(f)的影响。在存在AVP（100 μU/ml）时，J(v)和P(f)分别为1.04±0.10和202.6±17.2，在存在AVP（10 μU/ml）时分别为1.06±0.18和193.4±27.7。然而，在存在浓度为2.5 μU/ml的AVP时，J(v)为0.60±0.07，P(f)为100.7±24.7。ISO（10(-6)和10(-5) M）在上述最大和次最大浓度的AVP存在时没有任何显著影响。在不存在AVP的情况下，对照J(v)为0.01±0.12，P(f)为4.6±11.0。在25或37摄氏度下添加ISO不会导致J(v)或P(f)有任何显著变化。这些研究表明，α-肾上腺素能激动剂在肾小管水平直接抑制AVP介导的水吸收，这种作用可被特异性α-肾上腺素能拮抗剂阻断。这种作用似乎是在腺苷酸环化酶激活水平发挥的，因为在存在cAMP时不存在这种作用。β-肾上腺素能激动剂在肾小管水平不会直接抑制或增强AVP介导的水吸收。
