Activation of muscarinic acetylcholine receptors elicits pigment granule dispersion in retinal pigment epithelium isolated from bluegill

González, Alfredo; Crittenden, Elizabeth L.; Garcia, Dana

doi:10.1186/1471-2202-5-23

Cited by 15 publications

(26 citation statements)

References 27 publications

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“…In the present study we extended earlier pharmacological studies by employing additional subtype-specific antagonists not tested by González et al (2004) for M 1 , M 2 and M 3 receptors. M 5 -selective agents were not available.…”

Section: Discussionmentioning

confidence: 83%

“…show carbachol at nanomolar concentrations operates through muscarinic receptors to induce pigment granule dispersion in bluegill RPE. Furthermore, González et al (2004) observed that antagonists specific for M 2 and M 4 receptors failed to block carbachol-induced pigment granule dispersion, and an agonist specific for M 2 receptors failed to induce pigment granule dispersion. In contrast, antagonists specific for M 1 and M 3 receptors blocked carbachol-induced pigment granule dispersion, and an agonist specific for M 1 receptors activated dispersion.…”

Section: Discussionmentioning

confidence: 96%

“…Pharmacological experiments were carried out following the method of González et al (2004). In brief, fish were dark adapted for 30 min in a light-tight box 6 h after the onset of light.…”

Section: Pharmacological Analysis Of Signaling Pathwaysmentioning

confidence: 99%

“…Recently, activation of muscarinic receptors was found to elicit pigment granule dispersion in retinal pigment epithelium (RPE) isolated from bluegill (González et al 2004). The RPE is a monolayer of cells forming a tissue located between the neural retina and the choroid (Zinn and Marmor 1979), and pigment granule movement in RPE is a light-adaptive mechanism in fish.…”

mentioning

confidence: 99%

“…From studies using the cholinergic agonist carbamyl choline (carbachol), García (1998) suggested that ACh might play a role in light-adaptive pigment granule dispersion in green sunfish (Lepomis cyanellus). González et al (2004) reported that carbachol-induced pigment granule dispersion in RPE isolated from bluegill (L. macrochirus) is mediated by a muscarinic receptor and inferred that it belonged to one of the oddnumbered subclasses. This inference was based on pharmacological evidence that antagonists specific for M 1 and M 3 muscarinic receptors blocked pigment granule dispersion, whereas an agonist specific for the M 1 receptor activated dispersion.…”

mentioning

confidence: 99%

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Molecular and pharmacological characterization of muscarinic receptors in retinal pigment epithelium: role in light‐adaptive pigment movements

Phatarpekar

Durdan

Copeland

et al. 2005

Journal of Neurochemistry

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Muscarinic receptors are the predominant cholinergic receptors in the central and peripheral nervous systems. Recently, activation of muscarinic receptors was found to elicit pigment granule dispersion in retinal pigment epithelium isolated from bluegill fish. Pigment granule movement in retinal pigment epithelium is a light-adaptive mechanism in fish. In the present study, we used pharmacological and molecular approaches to identify the muscarinic receptor subtype and the intracellular signaling pathway involved in the pigment granule dispersion in retinal pigment epithelium. Of the muscarinic receptor subtype-specific antagonists used, only antagonists specific for M 1 and M 3 muscarinic receptors were found to block carbamyl choline (carbachol)-induced pigment granule dispersion. A phospholipase C inhibitor also blocked carbacholinduced pigment granule dispersion, and a similar result was obtained when retinal pigment epithelium was incubated with an inositol trisphosphate receptor inhibitor. We isolated M 2 and M 5 receptor genes from bluegill and studied their expression. Only M 5 was found to be expressed in retinal pigment epithelium. Taken together, pharmacological and molecular evidence suggest that activation of an odd subtype of muscarinic receptor, possibly M 5 , on fish retinal pigment epithelium induces pigment granule dispersion.

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Section: Discussionmentioning

confidence: 83%

Section: Discussionmentioning

confidence: 96%

“…Pharmacological experiments were carried out following the method of González et al (2004). In brief, fish were dark adapted for 30 min in a light-tight box 6 h after the onset of light.…”

Section: Pharmacological Analysis Of Signaling Pathwaysmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Molecular and pharmacological characterization of muscarinic receptors in retinal pigment epithelium: role in light‐adaptive pigment movements

Phatarpekar

Durdan

Copeland

et al. 2005

Journal of Neurochemistry

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Muscarinic Receptor Agonists and Antagonists: Effects on Ocular Function

Mitchelson

2011

Handbook of Experimental Pharmacology

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Muscarinic agonists act mainly via muscarinic M₃ cholinoceptors to cause contraction of the iris sphincter, ciliary muscle and trabecular meshwork as well as increase outflow facility of aqueous humour. In the iris dilator, the effect of muscarinic agonists is species dependent but is predominantly relaxation via muscarinic M₃ receptors. In the conjunctiva, muscarinic agonists stimulate goblet cell secretion which contributes to the protective tear film. Muscarinic M₂ and M₃ receptors appear mainly involved. In the lens muscarinic agonists act via muscarinic M₁ receptors to produce depolarization and increase [Ca(2+)](i). All five subtypes of muscarinic receptor are present in the retina. In the developing retina, acetylcholine appears to limit purinergic stimulation of retinal development and decrease cell proliferation. In the adult retina acetylcholine and other muscarinic agonists may have complex effects, for example, enhancing light-evoked neuronal firing in transient ON retinal ganglion cells and inhibiting firing in OFF retinal ganglion cells. In the lacrimal gland, muscarinic agonists activate M₃ receptors on secretory globular acinar cells to stimulate tear secretion and also cause contraction of myoepithelial cells. In Sjögren's syndrome, antibodies to the muscarinic M₃ receptor disrupt normal gland function leading to xerophthalmia although the mechanism of action of the antibody is still not clear. Atropine and pirenzepine are useful in limiting the development of myopia in children probably by an action on muscarinic receptors in the sclera, although many other muscarinic receptor antagonists are not effective.

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