RGD Reference Report - Angiotensin receptor subtypes in thin and muscular juxtamedullary efferent arterioles of rat kidney. - Rat Genome Database

Send us a Message



Submit Data |  Help |  Video Tutorials |  News |  Publications |  Download |  REST API |  Citing RGD |  Contact   

Angiotensin receptor subtypes in thin and muscular juxtamedullary efferent arterioles of rat kidney.

Authors: Helou, CM  Imbert-Teboul, M  Doucet, A  Rajerison, R  Chollet, C  Alhenc-Gelas, F  Marchetti, J 
Citation: Helou CM, etal., Am J Physiol Renal Physiol 2003 Sep;285(3):F507-14. Epub 2003 May 6.
RGD ID: 1298648
Pubmed: PMID:12734102   (View Abstract at PubMed)
DOI: DOI:10.1152/ajprenal.00430.2002   (Journal Full-text)

ANG II controls the vascular tone of pre- and postglomerular arterioles, and thereby glomerular filtration, through binding to either AT1A, AT1B, or AT2 receptors. AT1 receptors, which are coupled to intracellular Ca2+ signaling, have vasoconstricting effects, whereas AT2 receptors, whose signaling mechanism is unknown, induce vasodilatation. The angiotensin receptors have been characterized in afferent arterioles, which express the three types of receptors, but not in efferent arterioles. Two subpopulations of juxtamedullary efferent arterioles, muscular ones which terminate as vasa rectae and thin ones which terminate as peritubular capillaries, have been described. They display functional heterogeneity with regard to the ANG II response. To evaluate whether these differences are associated with differential expression of ANG II receptors, we examined the expression pattern of AT1A, AT1B, and AT2 receptor mRNAs by RT-PCR in these arterioles and studied the effect of valsartan, a specific AT1-receptor antagonist. Results indicate that muscular arterioles express AT1A, AT1B, and AT2 receptors, whereas thin arterioles only express the AT1A and AT2 types, and at a much lower level. Valsartan fully inhibited ANG II-induced increases in intracellular Ca2+ in both arteriolar types, but with different kinetics. In muscular arterioles, inhibition was monoexponential, whereas it displayed a marked positive cooperativity in thin arterioles. Finally, the apparent affinity for valsartan was higher in muscular than in thin arterioles. In conclusion, this study further documents the differences between muscular and thin efferent arterioles with regard to ANG II signalization in the rat kidney.

Objects referenced in this article
Gene Agtr1a angiotensin II receptor, type 1a Rattus norvegicus
Gene Agtr1b angiotensin II receptor, type 1b Rattus norvegicus
Gene Agtr2 angiotensin II receptor, type 2 Rattus norvegicus

Additional Information