Author(s): Fleming JT, Parekh N, Steinhausen M
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Abstract The hydronephrotic kidney of Inactin-anesthetized female Wistar rats was exteriorized in a controlled bath to directly observe preglomerular and postglomerular vessels via television microscopy. Nitrendipine, added to the bath in a concentration that did not alter blood pressure, induced a concentration-dependent dilation of preglomerular vessels. The arcuate artery maximally dilated by 29 +/- 4\%, the interlobular artery by 24 +/- 5\%, the afferent arteriole near the interlobular artery by 60 +/- 9\%, and near the glomerulus by 28 +/- 13\%. In contrast the efferent arteriole near the glomerulus dilated by only 11 +/- 6\% and near the welling point by 7 +/- 9\%. Similarly, diltiazem significantly dilated preglomerular vessels but not efferent arterioles. Acetylcholine significantly dilated all preglomerular vessels and dilated the afferent arterioles near the glomerulus (by 51 +/- 8\%) to a greater extent than the calcium blockers. Acetylcholine also significantly dilated the efferent arterioles (near the glomerulus by 26 +/- 5\% and near the welling point by 12 +/- 3\%). These data suggest that the tone of the preglomerular vessels of the hydronephrotic kidney is more dependent on the entry of extracellular calcium through calcium antagonist-sensitive channels (i.e., potential dependent) than is the tone of the afferent arterioles near the glomerulus and the efferent arterioles.
This article was published in Am J Physiol
and referenced in Medical & Surgical Urology