Published 6 issues per year
ISSN Print: 1045-4403
ISSN Online: 2162-6502
Indexed in
Calcium Signaling in Ocular Arterioles
ABSTRACT
Local control of blood flow to the photoreceptors and associated neurons in the retina is largely achieved through changes in tone within the choroidal and retinal arterioles. This is primarily achieved through changes in [Ca2+] within the smooth muscle of these vessels, which regulates cell contraction and vascular constriction. Here we review some aspects of the cell physiology involved in these Ca2+-signaling processes, with particular emphasis on the molecular mechanisms involved. Ca2+-influx across the plasma membrane can occur via a variety of Ca2+-channels, including voltage-operated, store-operated, and receptor-operated channels. Ca2+ may also be released from intracellular stores via RyR-, or IP3R-gated channels in the SR membrane. Using high-speed confocal Ca2+-imaging, we have also demonstrated that the resulting signals are far from homogeneous, with spontaneous activity in retinal arterioles being characterized by both localized Ca2+-sparks and more global Ca2+-waves and oscillations. These signals may be specifically and differentially targeted, for example, to Ca2+-sensitive ion channels (stimulus-excitation coupling), or pathways regulating contraction (stimulus-contraction coupling). Exploring the role of changes in such targeting in disease states will provide exciting opportunities for future research.
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MCGAHON MARY K., MCKEE JONATHAN, DASH DURGA P., BROWN EOIN, SIMPSON DAVID A., CURTIS TIMOTHY M., McGEOWN JAMES G., SCHOLFIELD CHARLES N., Pharmacological Profiling of Store-Operated Ca2+Entry in Retinal Arteriolar Smooth Muscle, Microcirculation, 19, 7, 2012. Crossref
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Zhou Rong, Chen Feng, Li Qiang, Hu De-yao, Liu Liang-ming, Stimulation of the adenosine A3 receptor reverses vascular hyporeactivity after hemorrhagic shock in rats, Acta Pharmacologica Sinica, 31, 4, 2010. Crossref
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Misfeldt Mikkel Wölck, Aalkjaer Christian, Simonsen Ulf, Bek Toke, Voltage-gated calcium channels are involved in the regulation of calcium oscillations in vascular smooth muscle cells from isolated porcine retinal arterioles, Experimental Eye Research, 91, 1, 2010. Crossref