| First Author | Gericke A | Year | 2011 |
| Journal | Invest Ophthalmol Vis Sci | Volume | 52 |
| Issue | 10 | Pages | 7479-84 |
| PubMed ID | 21873683 | Mgi Jnum | J:181589 |
| Mgi Id | MGI:5312003 | Doi | 10.1167/iovs.11-7370 |
| Citation | Gericke A, et al. (2011) Identification of the muscarinic acetylcholine receptor subtype mediating cholinergic vasodilation in murine retinal arterioles. Invest Ophthalmol Vis Sci 52(10):7479-84 |
| abstractText | PURPOSE: To identify the muscarinic acetylcholine receptor subtype that mediates cholinergic vasodilation in murine retinal arterioles. METHODS: Muscarinic receptor gene expression was determined in murine retinal arterioles using real-time PCR. To assess the functional relevance of muscarinic receptors for mediating vascular responses, retinal vascular preparations from muscarinic receptor-deficient mice were studied in vitro. Changes in luminal arteriole diameter in response to muscarinic and nonmuscarinic vasoactive substances were measured by video microscopy. RESULTS: Only mRNA for the M(3) receptor was detected in retinal arterioles. Thus, M(3) receptor-deficient mice (M3R(-/-)) and respective wild-type controls were used for functional studies. Acetylcholine concentration-dependently dilated retinal arterioles from wild-type mice. In contrast, vasodilation to acetylcholine was almost completely abolished in retinal arterioles from M3R(-/-) mice, whereas responses to the nitric oxide (NO) donor nitroprusside were retained. Carbachol, an acetylcholinesterase-resistant analog of acetylcholine, also evoked dilation in retinal arterioles from wild-type, but not from M3R(-/-), mice. Vasodilation responses from wild-type mice to acetylcholine were negligible after incubation with the non-subtype-selective muscarinic receptor blocker atropine or the NO synthase inhibitor N(omega)-nitro-L-arginine methyl ester, and were even reversed to contraction after endothelial damage with 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate. CONCLUSIONS: These findings provide evidence that endothelial M(3) receptors mediate cholinergic vasodilation in murine retinal arterioles via activation of NO synthase. |
