The study toward the development of specific agonist and antagonist for the purinergic receptors in the kidney

1996年至1998年研究成果我们已经决定了以下的追随者，In order to determine the存在的ATP receptors alongnephron segment,我们投资a [Ca D22+ D2]I increase induced by ATP and its analogs in isolated single nephronsegment. An increase of [Ca D22+ D2]I was observed in the glomerulus，proximal tubule and outer medullar collecting duct （OMCD）和subtypes were determined to be P2Y1 of P2Y2. After being treated with ATP，a [Ca D22+ D2]I increase was not observed by addition of several peptide hormones，such as AVP and ANG II，在nephron segments. This结果suggests that ATP receptor might modulate the renal effect ofthese hormones.We also investigated the existence of ATP receptors in the renal cultured cells which我们established from the distinct nephron segments derived from SV40 large T antigen transgenicmRNA expression of P2X and P2Y purinoceptors detected in The culture cells of mouseS1 (early convoluted segment of proximal tubule) and OMCD. Addition of ATP and its analogs inducedthe [Ca D22+ D2]I increase in both of the cells.In addition，rat cultured mesangial cells expressed the P2Y and P2X purinoceptors，and showed the [Ca D22+ D2]I increase induced by ATP. Phosphorylation of myosin light chain wasnot detected by the stimulation of ATP receptors of mesangial cells.Thus，this project revealed the existence of certain subtypes of purinoceptors in the kidney and renalculture cells. We also implicated several physiological roles of purinoceptors of the kidney. Wehope that the findings obtained in this project will promote the understanding the physiologicalsignificance of purinoceptors，and provide the basis on the development of agonist and antagonist of the purinoceptors。

During the research performed from 1996 to 1998, we obtained the following results. In order to determine the existence of the ATP receptors along nephron segment, we investigated a [CaィイD22+ィエD2]I increase induced by ATP and its analogs in isolated single nephron segment. An increase of [CaィイD22+ィエD2]I was observed in the glomerulus, proximal tubule and outer medullar collecting duct (OMCD), and the subtypes were determined to be P2Y1 of P2Y2. After being treated with ATP, a [CaィイD22+ィエD2]I increase was not observed by addition of several peptide hormones, such as AVP and ANG II, in the nephron segments. This result suggests that ATP receptor might modulate the renal effect of these hormones.We also investigated the existence of ATP receptors in the renal cultured cells which we established from the distinct nephron segments derived from SV40 large T antigen transgenic mouse. The mRNA expression of P2X and P2Y purinoceptors were detected in the culture cells of mouse S1 (early convoluted segment of proximal tubule) and OMCD. Addition of ATP and its analogs induced the [CaィイD22+ィエD2]I increase in both of the cells.In addition, rat cultured mesangial cells expressed the P2Y and P2X purinoceptors, and showed the [CaィイD22+ィエD2]I increase induced by ATP. Phosphorylation of myosin light chain was not detected by the stimulation of ATP receptors of mesangial cells.Thus, this project revealed the existence of certain subtypes of purinoceptors in the kidney and renal culture cells. We also implicated several physiological roles of purinoceptors of the kidney. We hope that the findings obtained in this project will promote the understanding the physiological significance of purinoceptors, and provide the basis on the development of agonist and antagonist of the purinoceptors.