Muscarinic Receptor Subtypes Involved in Pigment Granule Dispersion in Retinal Pigment Epithelium




Copeland, Chad Michael

Journal Title

Journal ISSN

Volume Title



Previous studies have shown muscarinic receptors are involved in light driven pigment dispersion in retinal pigment epithelia (RPE). Pharmacological agents can be used to test this hypothesis and by selective inhibition, elucidate the sub-class of the receptor involved, and the intracellular downstream signaling pathway. RPE was isolated from Lepomis macrochirus, commonly known as bluegill, and treated with various pharmacological agents, including muscarinic receptor antagonists and agents to block second messenger pathway targets. Telenzepine and p-FHHSiD, M1 and M3 receptor antagonists, respectively, blocked pigment granule dispersion induced by carbachol, while methoctramine, an M2 antagonist did not. U73122 and 2-APB, a phospholipase C inhibitor and IP3-receptor antagonist, respectively, were also able to block carbachol-induce dispersion. Therefore, I conclude that carbachol-induced pigment dispersion 1s mediated through Modd receptors. I also propose that Ca2+ could be necessary for pigment dispersion induced by carbachol.



muscarinic receptors, rhodopsin, epithelium, dispersion


Copeland, C. M. (2005). Muscarinic receptor subtypes involved in pigment granule dispersion in retinal pigment epithelium (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.


Rights Holder

Rights License

Rights URI