| Full text | |
| Author(s): |
Antonio, Ligia Subitoni
[1]
;
Costa, Roberta Ribeiro
[1]
;
Gomes, Marcelo Damario
[2]
;
Varanda, Wamberto Antonio
[1]
Total Authors: 4
|
| Affiliation: | [1] Univ Sao Paulo, Sch Med, Dept Physiol, BR-14049900 Ribeirao Preto, SP - Brazil
[2] Univ Sao Paulo, Sch Med, Dept Biochem & Immunol, BR-14049900 Ribeirao Preto, SP - Brazil
Total Affiliations: 2
|
| Document type: | Journal article |
| Source: | PURINERGIC SIGNALLING; v. 5, n. 3, p. 277-287, SEP 2009. |
| Web of Science Citations: | 15 |
| Abstract | |
ATP acts on cellular membranes by interacting with P2X (ionotropic) and P2Y (metabotropic) receptors. Seven homomeric P2X receptors (P2X(1)-P2X(7)) and seven heteromeric receptors (P2X(1/2), P2X(1/4), P2X(1/5), P2X(2/3), P2X(2/6), P2X(4/6), P2X(4/7)) have been described. ATP treatment of Leydig cells leads to an increase in {[}Ca(2+)](i) and testosterone secretion, supporting the hypothesis that Ca(2+) signaling through purinergic receptors contributes to the process of testosterone secretion in these cells. Mouse Leydig cells have P2X receptors with a pharmacological and biophysical profile resembling P2X(2). In this work, we describe the presence of several P2X receptor subunits in mouse Leydig cells. Western blot experiments showed the presence of P2X(2), P2X(4), P2X(6), and P2X(7) subunits. These results were confirmed by immunofluorescence. Functional results support the hypothesis that heteromeric receptors are present in these cells since 0.5 mu M ivermectin induced an increase (131.2 +/- 5.9%) and 3 mu M ivermectin a decrease (64.2 +/- 4.8%) in the whole-cell currents evoked by ATP. These results indicate the presence of functional P2X(4) subunits. P2X(7) receptors were also present, but they were non-functional under the present conditions because dye uptake experiments with Lucifer yellow and ethidium bromide were negative. We conclude that a heteromeric channel, possibly P2X(2/4/6), is present in Leydig cells, but with an electrophysiological and pharmacological phenotype characteristic of the P2X(2) subunit. (AU) | |
| FAPESP's process: | 06/50954-7 - Ionic currents and receptors in the physiology of excitable and non-excitable cells |
| Grantee: | Wamberto Antonio Varanda |
| Support Opportunities: | Research Projects - Thematic Grants |