Bidirectional action of extracellular ATP on intracapillary volume of isolated rat renal glomeruli
Jankowski, M.; Szczepańska-Konkel, M.; Kalinowski, L.; Angielski, S.
Journal of Physiology and Pharmacology An Official Journal of the Polish Physiological Society 51(3): 491-496
2000
ISSN/ISBN: 0867-5910 PMID: 11016868 Document Number: 518662
Receptors for extracellular nucleotides (P2-purinoceptors) are expressed in renal glomerulus; both on mesangial and endothelial cells. In the present study we have evaluated the potential role of ATP in the regulation of glomerular contraction and relaxation. Using (3H)-inulin we measured the Glomerular Inulin Space (GIS), (that reflects mainly glomerular intracapillary volume), in the presence of ATP and its analogues e.g. 2-methylthio-ATP (P2Y-receptor agonist) and beta,gamma-methylene-ATP (P2X-receptor agonist). Incubation of the intact glomeruli with ATP or 2-methylthio-ATP or beta,gamma-methylene-ATP induced a decrease of GIS in similar magnitude as angiotensin II e.g.: about 10% of the basal value. When glomeruli were precontracted with angiotensin II it was observed that both ATP and 2-methylthio-ATP induced an increase of GIS to the basal value, similarly to atrial natriuretic factor. Furthermore, there was no relaxing effect with beta,gamma-methylene-ATP. We suggest that, these bidirectional changes of the intracapillary volume induced by the extracellular ATP may contribute to regulation of glomerular dynamics.