Owen M P, Taphorn M C, Walmsley J G
Department of Biomedical Sciences, University of Illinois College of Medicine Rockford, 61107.
Am J Physiol. 1989 Mar;256(3 Pt 2):H607-12. doi: 10.1152/ajpheart.1989.256.3.H607.
A comparative study of the adrenergic control of two sequential rabbit intrarenal arteries of differing diameter [intrarenal branch artery (IRBA)-unstretched lumen diameter (ULD) approximately 300 microns and interlobar artery (ILA)-ULD approximately 250 microns] has been conducted. The neurogenic contractile response of isolated segments in relation to the maximum response to l-norepinephrine (NE) was minimal (8 Hz response approximately 30% of maximum contraction) and similar in both types of arteries. Phentolamine (PTA) (10(-6) M) blocked neurally evoked contractions of the IRBAs at 2, 4, and 8 Hz and of the ILAs at 2 and 4 Hz. (8 Hz responses were not entirely blocked in 3 out of 8 ILAs.) The sensitivity to exogenous NE decreased with a decrease in intrarenal vessel diameter, whereas the maximum active smooth muscle cell stress to NE was greater than 3 X 10(5) N/m2 for each vessel. All arterial segments constricted in response to histamine (H) and NE with equal maximal effects; however, sensitivity to H was greater in the smaller artery (ILA). The comparative contractile responses to nerve stimulation and exogenous NE in sequential renal arteries contrasts to the pattern of these responses in sequential arteries in any other rabbit regional bed previously studied (pulmonary and ear vasculature).
对两只家兔不同直径的两条连续肾内动脉[肾内分支动脉（IRBA）-未拉伸管腔直径（ULD）约300微米和叶间动脉（ILA）-ULD约250微米]的肾上腺素能控制进行了一项比较研究。分离节段的神经源性收缩反应与对l-去甲肾上腺素（NE）的最大反应相关，该反应最小（8赫兹反应约为最大收缩的30%），且在两种类型的动脉中相似。酚妥拉明（PTA）（10^(-6) M）可阻断2、4和8赫兹时IRBA的神经诱发收缩以及2和4赫兹时ILA的神经诱发收缩。（8赫兹反应在8个ILA中有3个未被完全阻断。）对去甲肾上腺素的敏感性随着肾内血管直径的减小而降低，而每种血管对去甲肾上腺素的最大活性平滑肌细胞应力大于3×10^5 N/m²。所有动脉节段对组胺（H）和去甲肾上腺素的收缩反应具有相同的最大效应；然而，较小的动脉（ILA）对组胺的敏感性更高。连续肾动脉对神经刺激和外源性去甲肾上腺素的比较收缩反应与之前研究的家兔任何其他局部床（肺和耳血管系统）中连续动脉的这些反应模式形成对比。
