Bidirectional action of extracellular ATP on intracapillary volume of isolated rat renal glomeruli.
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.
Jankowski
M
M
Department of Clinical Biochemistry, Medical University of Gdańsk, Poland. majank@amedec.amg.gda.pl
Szczepańska-Konkel
M
M
Kalinowski
L
L
Angielski
S
S
D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology*; D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D007678:Kidney Glomerulus / Q000098:blood supply / Q000187:drug effects* / Q000502:physiology; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D011983:Receptors, Purinergic / Q000187:drug effects / Q000502:physiology; D013873:Thionucleotides / Q000494:pharmacology; D014662:Vasoconstrictor Agents / Q000494:pharmacology
D011983:Receptors, Purinergic; D013873:Thionucleotides; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; D000255:Adenosine Triphosphate; C002630:alpha,beta-methyleneadenosine 5'-triphosphate; C008501:2-methylthio-ATP