| First Author | Baker SA | Year | 2013 |
| Journal | J Physiol | Volume | 591 |
| Issue | 24 | Pages | 6193-208 |
| PubMed ID | 24144881 | Mgi Jnum | J:216204 |
| Mgi Id | MGI:5607860 | Doi | 10.1113/jphysiol.2013.264747 |
| Citation | Baker SA, et al. (2013) Distribution and Ca(2+) signalling of fibroblast-like (PDGFR(+)) cells in the murine gastric fundus. J Physiol 591(Pt 24):6193-208 |
| abstractText | Platelet-derived growth factor receptor alpha positive (PDGFRalpha(+)) cells are suggested to mediate purinergic inputs in GI muscles, but the responsiveness of these cells to purines in situ has not been evaluated. We developed techniques to label and visualize PDGFRalpha(+) cells in murine gastric fundus, load cells with Ca(2+) indicators, and follow their activity via digital imaging. Immunolabelling demonstrated a high density of PDGFRalpha(+) cells in the fundus. Cells were isolated and purified by fluorescence-activated cell sorting (FACS) using endogenous expression of enhanced green fluorescent protein (eGFP) driven off the Pdgfra promoter. Quantitative PCR showed high levels of expression of purinergic P2Y1 receptors and SK3 K(+) channels in PDGFRalpha(+) cells. Ca(2+) imaging was used to characterize spontaneous Ca(2+) transients and responses to purines in PDGFRalpha(+) cells in situ. ATP, ADP, UTP and beta-NAD elicited robust Ca(2+) transients in PDGFRalpha(+) cells. Ca(2+) transients were also elicited by the P2Y1-specific agonist (N)-methanocarba-2MeSADP (MRS-2365), and inhibited by MRS-2500, a P2Y1-specific antagonist. Responses to ADP, MRS-2365 and beta-NAD were absent in PDGFRalpha(+) cells from P2ry1((-/-)) mice, but responses to ATP were retained. Purine-evoked Ca(2+) transients were mediated through Ca(2+) release mechanisms. Inhibitors of phospholipase C (U-73122), IP3 (2-APB), ryanodine receptors (Ryanodine) and SERCA pump (cyclopiazonic acid and thapsigargin) abolished Ca(2+) transients elicited by purines. This study provides a link between purine binding to P2Y1 receptors and activation of SK3 channels in PDGFRalpha(+) cells. Activation of Ca(2+) release is likely to be the signalling mechanism in PDGFRalpha(+) cells responsible for the transduction of purinergic enteric inhibitory input in gastric fundus muscles. |
