P1-/P2-purinergic receptors on cultured rabbit retinal Müller cells.
Adenosine 5'-triphosphate (ATP) and its metabolic products function as neurotransmitters or neuromodulators under the control of P1/P2-purinergic receptors. To determine the presence of these receptors on retinal Müller cells, spectrofluorometry was carried out on intracellular calcium mobilization, using Fura-2 images. Müller cells were cultured from adult rabbit retinas. Cytosolic calcium ([Ca2+]i) increased dose dependently with the application of ATP. This response was not blocked when a calcium channel blocker, nifedipine, was present, but this response was blocked, for the most part, when a P2 receptor antagonist, pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid (PPADS) was present. Increase in [Ca2+]i was noted by the A1 or A2 agonist, which was blocked completely by each antagonist. Response to the A1 agonist was apparent only at high concentrations. Increase in [Ca2+]i was seen in some cells following administration of the P2x agonist, methylene ATP, only at a high concentration (100 microM) but not in the presence of PPADS (50 nM). The greatest increase in [Ca2+]i was induced by a P2y agonist, methyl thio ATP at 1 to 10 microM, which was completely blocked by PPADS. Cultured Müller cells are thus shown quite likely to possess the P1-/P2-purinergic receptors including A2 and P2y.
Liu
Y
Y
Department of Ophthalmology, Kitasato University School of Medicine, Sagamihara, Japan.
Wakakura
M
M
D000241:Adenosine / Q000031:analogs & derivatives / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D016257:Fura-2 / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism*; D058919:Purinergic P2 Receptor Antagonists; D011732:Pyridoxal Phosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D011817:Rabbits; D018047:Receptors, Purinergic P1 / Q000378:metabolism*; D018048:Receptors, Purinergic P2 / Q000378:metabolism*; D012160:Retina / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013050:Spectrometry, Fluorescence
D058919:Purinergic P2 Receptor Antagonists; D018047:Receptors, Purinergic P1; D018048:Receptors, Purinergic P2; C077792:pyridoxal phosphate-6-azophenyl-2',4'-disulfonic acid; D011732:Pyridoxal Phosphate; D000255:Adenosine Triphosphate; D000241:Adenosine; D002118:Calcium; D016257:Fura-2