Calcium antagonists preferentially dilate preglomerular vessels of hydronephrotic kidney
Fleming, J.T.; Parekh, N.; Steinhausen, M.
American Journal of Physiology 253(6 Pt 2): F1157-F1163
1987
ISSN/ISBN: 0002-9513 PMID: 3425725 Document Number: 298894
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 vessles 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.