{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T06:49:17Z","timestamp":1791960557093,"version":"4.3.4"},"reference-count":55,"publisher":"American Physiological Society","issue":"4","content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["American Journal of Physiology-Cell Physiology"],"published-print":{"date-parts":[[2004,10]]},"abstract":"<jats:p> The eye\u2019s aqueous humor is secreted by a bilayered ciliary epithelium comprising pigmented (PE) and nonpigmented (NPE) epithelial cell layers. Stromal Cl<jats:sup>\u2212<\/jats:sup> enters the PE cells and crosses gap junctions to the NPE cells for release into the aqueous humor. Maxi-Cl<jats:sup>\u2212<\/jats:sup> channels are expressed in PE cells, but their physiological significance is unclear. To address this question, excised patches and whole native bovine PE cells were patch clamped, and volume was monitored by calcein fluorescence. In symmetrical 130 mM NaCl, cAMP at the cytoplasmic surface of inside-out patches produced concentration-dependent activation of maxi-Cl<jats:sup>\u2212<\/jats:sup> channels with a unitary conductance of 272 \u00b1 2 pS ( n = 80). Voltage steps from 0 to \u00b180 mV, but not to \u00b140 mV, produced rapid channel inactivation consistent with the typical characteristics of maxi-Cl<jats:sup>\u2212<\/jats:sup> channels. cAMP also activated the maxi-Cl<jats:sup>\u2212<\/jats:sup> channels in outside-out patches. In both cases, maxi-Cl<jats:sup>\u2212<\/jats:sup> channels were reversibly inhibited by SITS and 5-nitro-2-(phenylpropylamino)benzoate (NPPB). Decreasing cytoplasmic Cl<jats:sup>\u2212<\/jats:sup> concentration reduced both open-channel probability and unitary conductance. Similarly, the membrane-permeant 8-bromo-cAMP stimulated outward and inward whole cell currents; the stimulation was larger at higher intracellular Cl<jats:sup>\u2212<\/jats:sup> concentration. As with unitary currents, cAMP-triggered whole cell currents displayed inactivation at \u00b180 but not at \u00b140 mV. Moreover, cAMP triggered NPPB-sensitive shrinkage of PE cells. The results suggest that cAMP directly activates maxi-Cl<jats:sup>\u2212<\/jats:sup> channels of native PE cells that contribute to Cl<jats:sup>\u2212<\/jats:sup> release particularly from Cl<jats:sup>\u2212<\/jats:sup>-loaded cells. These cAMP-activated channels provide a potential mechanism for reducing and modulating net aqueous humor secretion by facilitating Cl<jats:sup>\u2212<\/jats:sup> reabsorption into the ciliary stroma. <\/jats:p>","DOI":"10.1152\/ajpcell.00175.2004","type":"journal-article","created":{"date-parts":[[2004,6,15]],"date-time":"2004-06-15T18:12:01Z","timestamp":1087323121000},"page":"C1003-C1011","source":"Crossref","is-referenced-by-count":30,"title":["cAMP-activated maxi-Cl<sup>\u2212<\/sup> channels in native bovine pigmented ciliary epithelial cells"],"prefix":"10.1152","volume":"287","author":[{"given":"Chi-Wai","family":"Do","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Kim","family":"Peterson-Yantorno","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Claire H.","family":"Mitchell","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mortimer M.","family":"Civan","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"24","reference":[{"key":"R1","doi-asserted-by":"crossref","unstructured":"Bathori G, Parolini I, Szabo I, Tombola F, Messina A, Oliva M, Sargiacomo M, De Pinto V, and Zoratti M. Extramitochondrial porin: facts and hypotheses. J Bioenerg Biomembr 32: 79\u201389, 2000.","DOI":"10.1023\/A:1005516513313"},{"key":"R2","doi-asserted-by":"crossref","unstructured":"Bathori G, Parolini I, Tombola F, Szabo I, Messina A, Oliva M, De Pinto V, Lisanti M, Sargiacomo M, and Zoratti M. Porin is present in the plasma membrane where it is concentrated in caveolae and caveolae-related domains. J Biol Chem 274: 29607\u201329612, 1999.","DOI":"10.1074\/jbc.274.42.29607"},{"key":"R3","doi-asserted-by":"crossref","unstructured":"Becq F, Fanjul M, Mahieu I, Berger Z, Gola M, and Hollande E. Anion channels in a human pancreatic cancer cell line (Capan-1) of ductal origin. Pfl\u00fcgers Arch 420: 46\u201353, 1992.","DOI":"10.1007\/BF00378640"},{"key":"R4","doi-asserted-by":"crossref","unstructured":"Berrier C, Besnard M, and Ghazi A. Electrophysiological characteristics of the PhoE porin channel from Escherichia coli. Implications for the possible existence of a superfamily of ion channels. J Membr Biol 156: 105\u2013115, 1997.","DOI":"10.1007\/s002329900193"},{"key":"R5","doi-asserted-by":"crossref","unstructured":"Bertran GC and Kotsias BA. Chloride channels in toad skeletal muscle fibers. J Exp Zool 287: 423\u2013431, 2000.","DOI":"10.1002\/1097-010X(20001101)287:6<423::AID-JEZ3>3.0.CO;2-R"},{"key":"R6","doi-asserted-by":"crossref","unstructured":"Blatz AL and Magleby KL. Single voltage-dependent chloride-selective channels of large conductance in cultured rat muscle. Biophys J 43: 237\u2013241, 1983.","DOI":"10.1016\/S0006-3495(83)84344-6"},{"key":"R7","doi-asserted-by":"crossref","unstructured":"Caprioli J and Sears M. Forskolin lowers intraocular pressure in rabbits, monkeys, and man. Lancet 1: 958\u2013960, 1983.","DOI":"10.1016\/S0140-6736(83)92084-6"},{"key":"R8","unstructured":"Caprioli J, Sears M, Bausher L, Gregory D, and Mead A. Forskolin lowers intraocular pressure by reducing aqueous inflow. Invest Ophthalmol Vis Sci 25: 268\u2013277, 1984."},{"key":"R9","doi-asserted-by":"crossref","unstructured":"Carre DA, Tang CS, Krupin T, and Civan MM. Effect of bicarbonate on intracellular potential of rabbit ciliary epithelium. Curr Eye Res 11: 609\u2013624, 1992.","DOI":"10.3109\/02713689209000734"},{"key":"R10","doi-asserted-by":"crossref","unstructured":"Chen S, Inoue R, Inomata H, and Ito Y. Role of cyclic AMP-induced Cl conductance in aqueous humour formation by the dog ciliary epithelium. Br J Pharmacol 112: 1137\u20131145, 1994.","DOI":"10.1111\/j.1476-5381.1994.tb13202.x"},{"key":"R11","doi-asserted-by":"crossref","unstructured":"Chen S and Sears M. A low conductance chloride channel in the basolateral membranes of the non-pigmented ciliary epithelium of the rabbit eye. Curr Eye Res 16: 710\u2013718, 1997.","DOI":"10.1076\/ceyr.16.7.710.5064"},{"key":"R12","doi-asserted-by":"crossref","unstructured":"Civan MM. Transport by the ciliary epithelium of the eye. News Physiol Sci 12: 158\u2013162, 1997.","DOI":"10.1152\/physiologyonline.1997.12.4.158"},{"key":"R13","doi-asserted-by":"crossref","unstructured":"Coca-Prados M, Anguita J, Chalfant ML, and Civan MM. PKC-sensitive Cl\u2212 channels associated with ciliary epithelial homologue of pICln. Am J Physiol Cell Physiol 268: C572\u2013C579, 1995.","DOI":"10.1152\/ajpcell.1995.268.3.C572"},{"key":"R14","unstructured":"Crook RB, Takahashi K, Mead A, Dunn JJ, and Sears ML. The role of NaKCl cotransport in blood-to-aqueous chloride fluxes across rabbit ciliary epithelium. Invest Ophthalmol Vis Sci 41: 2574\u20132583, 2000."},{"key":"R15","doi-asserted-by":"crossref","unstructured":"Dermietzel R, Hwang TK, Buettner R, Hofer A, Dotzler E, Kremer M, Deutzmann R, Thinnes FP, Fishman GI, Spray DC, and Siemen D. Cloning and in situ localization of a brain-derived porin that constitutes a large-conductance anion channel in astrocytic plasma membranes. Proc Natl Acad Sci USA 91: 499\u2013503, 1994.","DOI":"10.1073\/pnas.91.2.499"},{"key":"R16","doi-asserted-by":"crossref","unstructured":"Diaz M, Bahamonde MI, Lock H, Munoz FJ, Hardy SP, Posas F, and Valverde MA. Okadaic acid-sensitive activation of maxi Cl\u2212 channels by triphenylethylene antioestrogens in C1300 mouse neuroblastoma cells. J Physiol 536: 79\u201388, 2001.","DOI":"10.1111\/j.1469-7793.2001.00079.x"},{"key":"R17","unstructured":"Do CW and Civan MM. Basis of chloride transport in ciliary epithelium. J Membr Biol. In press."},{"key":"R18","unstructured":"Do CW and To CH. Chloride secretion by bovine ciliary epithelium: a model of aqueous humor formation. Invest Ophthalmol Vis Sci 41: 1853\u20131860, 2000."},{"key":"R19","doi-asserted-by":"crossref","unstructured":"Dutta AK, Okada Y, and Sabirov RZ. Regulation of an ATP-conductive large-conductance anion channel and swelling-induced ATP release by arachidonic acid. J Physiol 542: 803\u2013816, 2002.","DOI":"10.1113\/jphysiol.2002.019802"},{"key":"R20","unstructured":"Edelman JL, Loo DD, and Sachs G. Characterization of potassium and chloride channels in the basolateral membrane of bovine nonpigmented ciliary epithelial cells. Invest Ophthalmol Vis Sci 36: 2706\u20132716, 1995."},{"key":"R21","doi-asserted-by":"crossref","unstructured":"Elena PP, Fredj-Reygrobellet D, Moulin G, and Lapalus P. Pharmacological characteristics of \u03b2-adrenergic-sensitive adenylate cyclase in non pigmented and in pigmented cells of bovine ciliary process. Curr Eye Res 3: 1383\u20131389, 1984.","DOI":"10.3109\/02713688409000833"},{"key":"R22","doi-asserted-by":"crossref","unstructured":"Falke LC and Misler S. Activity of ion channels during volume regulation by clonal N1E115 neuroblastoma cells. Proc Natl Acad Sci USA 86: 3919\u20133923, 1989.","DOI":"10.1073\/pnas.86.10.3919"},{"key":"R23","doi-asserted-by":"crossref","unstructured":"Fleischhauer JC, Beny JL, Flammer J, and Haefliger IO. Cyclic AMP and anionic currents in porcine ciliary epithelium. Klin Monatsbl Augenheilkd 218: 370\u2013372, 2001.","DOI":"10.1055\/s-2001-15903"},{"key":"R24","doi-asserted-by":"crossref","unstructured":"Fleischhauer JC, Mitchell CH, Peterson-Yantorno K, Coca-Prados M, and Civan MM. PGE2, Ca2+, and cAMP mediate ATP activation of Cl\u2212 channels in pigmented ciliary epithelial cells. Am J Physiol Cell Physiol 281: C1614\u2013C1623, 2001.","DOI":"10.1152\/ajpcell.2001.281.5.C1614"},{"key":"R25","unstructured":"Gaasterland D, Kupfer C, Ross K, and Gabelnick HL. Studies of aqueous humor dynamics in man. III. Measurements in young normal subjects using norepinephrine and isoproterenol. Invest Ophthalmol 12: 267\u2013279, 1973."},{"key":"R26","unstructured":"Green K, Bountra C, Georgiou P, and House CR. An electrophysiologic study of rabbit ciliary epithelium. Invest Ophthalmol Vis Sci 26: 371\u2013381, 1985."},{"key":"R27","unstructured":"Hurnak O and Zachar J. Maxi chloride channels in L6 myoblasts. Gen Physiol Biophys 11: 389\u2013400, 1992."},{"key":"R28","unstructured":"Hurnak O and Zachar J. Conductance-voltage relations in large-conductance chloride channels in proliferating L6 myoblasts. Gen Physiol Biophys 13: 171\u2013192, 1994."},{"key":"R29","unstructured":"Hurnak O and Zachar J. Selectivity of maxi chloride channels in the L6 rat muscle cell line. Gen Physiol Biophys 14: 91\u2013105, 1995."},{"key":"R30","doi-asserted-by":"crossref","unstructured":"Jacob TJ and Civan MM. Role of ion channels in aqueous humor formation. Am J Physiol Cell Physiol 271: C703\u2013C720, 1996.","DOI":"10.1152\/ajpcell.1996.271.3.C703"},{"key":"R31","doi-asserted-by":"crossref","unstructured":"Karaki SI and Kuwahara A. Regulation of intestinal secretion involved in the interaction between neurotransmitters and prostaglandin E2. Neurogastroenterol Motil 16, Suppl 1: 96\u201399, 2004.","DOI":"10.1111\/j.1743-3150.2004.00482.x"},{"key":"R32","unstructured":"Lee PY, Podos SM, Mittag T, and Severin C. Effect of topically applied forskolin on aqueous humor dynamics in cynomolgus monkey. Invest Ophthalmol Vis Sci 25: 1206\u20131209, 1984."},{"key":"R33","doi-asserted-by":"crossref","unstructured":"McCann FV, McCarthy DC, Keller TM, and Noelle RJ. Characterization of a large conductance non-selective anion channel in B lymphocytes. Cell Signal 1: 31\u201344, 1989.","DOI":"10.1016\/0898-6568(89)90018-1"},{"key":"R34","unstructured":"McCannel CA, Scanlon PD, Thibodeau S, and Brubaker RF. A study of aqueous humor formation in patients with cystic fibrosis. Invest Ophthalmol Vis Sci 33: 160\u2013164, 1992."},{"key":"R35","unstructured":"McLaughlin CW, Peart D, Purves RD, Carre DA, Macknight AD, and Civan MM. Effects of HCO3\u2212 on cell composition of rabbit ciliary epithelium: a new model for aqueous humor secretion. Invest Ophthalmol Vis Sci 39: 1631\u20131641, 1998."},{"key":"R36","doi-asserted-by":"crossref","unstructured":"Mitchell CH, Carre DA, McGlinn AM, Stone RA, and Civan MM. A release mechanism for stored ATP in ocular ciliary epithelial cells. Proc Natl Acad Sci USA 95: 7174\u20137178, 1998.","DOI":"10.1073\/pnas.95.12.7174"},{"key":"R37","doi-asserted-by":"crossref","unstructured":"Mitchell CH, Fleischhauer JC, Stamer WD, Peterson-Yantorno K, and Civan MM. Human trabecular meshwork cell volume regulation. Am J Physiol Cell Physiol 283: C315\u2013C326, 2002.","DOI":"10.1152\/ajpcell.00544.2001"},{"key":"R38","doi-asserted-by":"crossref","unstructured":"Mitchell CH, Wang L, and Jacob TJC. A large-conductance chloride channel in pigmented ciliary epithelial cells activated by GTP\u03b3S. J Membr Biol 158: 167\u2013175, 1997.","DOI":"10.1007\/s002329900254"},{"key":"R39","doi-asserted-by":"crossref","unstructured":"O\u2019Donnell MJ, Kelly SP, Nurse CA, and Wood CM. A maxi Cl\u2212 channel in cultured pavement cells from the gills of the freshwater rainbow trout Oncorhynchus mykiss. J Exp Biol 204: 1783\u20131794, 2001.","DOI":"10.1242\/jeb.204.10.1783"},{"key":"R40","doi-asserted-by":"crossref","unstructured":"Ostrom RS, Gregorian C, and Insel PA. Cellular release of and response to ATP as key determinants of the set-point of signal transduction pathways. J Biol Chem 275: 11735\u201311739, 2000.","DOI":"10.1074\/jbc.275.16.11735"},{"key":"R41","unstructured":"Raviola G and Raviola E. Intercellular junctions in the ciliary epithelium. Invest Ophthalmol Vis Sci 17: 958\u2013981, 1978."},{"key":"R42","doi-asserted-by":"crossref","unstructured":"Reymann S, Florke H, Heiden M, Jakob C, Stadtmuller U, Steinacker P, Lalk VE, Pardowitz I, and Thinnes FP. Further evidence for multitopological localization of mammalian porin (VDAC) in the plasmalemma forming part of a chloride channel complex affected in cystic fibrosis and encephalomyopathy. Biochem Mol Med 54: 75\u201387, 1995.","DOI":"10.1006\/bmme.1995.1011"},{"key":"R43","doi-asserted-by":"crossref","unstructured":"Roush ED and Kwatra MM. Human substance P receptor expressed in Chinese hamster ovary cells directly activates G\u03b1q\/11, G\u03b1s, and G\u03b1o. FEBS Lett 428: 291\u2013294, 1998.","DOI":"10.1016\/S0014-5793(98)00553-5"},{"key":"R44","doi-asserted-by":"crossref","unstructured":"Sabirov RZ, Dutta AK, and Okada Y. Volume-dependent ATP-conductive large-conductance anion channel as a pathway for swelling-induced ATP release. J Gen Physiol 118: 251\u2013266, 2001.","DOI":"10.1085\/jgp.118.3.251"},{"key":"R45","doi-asserted-by":"crossref","unstructured":"Schwiebert EM, Mills JW, and Stanton BA. Actin-based cytoskeleton regulates a chloride channel and cell volume in a renal cortical collecting duct cell line. J Biol Chem 269: 7081\u20137089, 1994.","DOI":"10.1016\/S0021-9258(17)37249-6"},{"key":"R46","doi-asserted-by":"crossref","unstructured":"Shahidullah M, Wilson WS, and Millar C. Effects of timolol, terbutaline and forskolin on IOP, aqueous humour formation and ciliary cyclic AMP levels in the bovine eye. Curr Eye Res 14: 519\u2013528, 1995.","DOI":"10.3109\/02713689508998398"},{"key":"R47","doi-asserted-by":"crossref","unstructured":"Shimizu S, Matsuoka Y, Shinohara Y, Yoneda Y, and Tsujimoto Y. Essential role of voltage-dependent anion channel in various forms of apoptosis in mammalian cells. J Cell Biol 152: 237\u2013250, 2001.","DOI":"10.1083\/jcb.152.2.237"},{"key":"R48","unstructured":"Stone RA. Nervous system and intraocular pressure. In: The Glaucomas (2nd ed.), edited by Ritch R, Shields MB, and Krupin T. St. Louis, MO: Mosby, 1996, p. 357\u2013383."},{"key":"R49","doi-asserted-by":"crossref","unstructured":"Strange K, Emma F, and Jackson PS. Cellular and molecular physiology of volume-sensitive anion channels. Am J Physiol Cell Physiol 270: C711\u2013C730, 1996.","DOI":"10.1152\/ajpcell.1996.270.3.C711"},{"key":"R50","doi-asserted-by":"crossref","unstructured":"Thinnes FP and Reymann S. New findings concerning vertebrate porin. Naturwissenschaften 84: 480\u2013498, 1997.","DOI":"10.1007\/s001140050432"},{"key":"R51","doi-asserted-by":"crossref","unstructured":"To CH, Do CW, Zamudio AC, and Candia OA. Model of ionic transport for bovine ciliary epithelium: effects of acetazolamide and HCO3\u2212. Am J Physiol Cell Physiol 280: C1521\u2013C1530, 2001.","DOI":"10.1152\/ajpcell.2001.280.6.C1521"},{"key":"R52","unstructured":"Wiederholt M, Helbig H, and Korbmacher C. Ion transport across the ciliary epithelium: lessons from cultured cells and proposed role of the carbonic anhydrase. In: Carbonic Anhydrase, edited by Botre F, Gross G, and Storey BT. New York: VCH, 1991, p. 232\u2013244."},{"key":"R53","doi-asserted-by":"crossref","unstructured":"Wiederholt M and Zadunaisky JA. Membrane potentials and intracellular chloride activity in the ciliary body of the shark. Pfl\u00fcgers Arch 407, Suppl 2: S112\u2013S115, 1986.","DOI":"10.1007\/BF00584939"},{"key":"R54","doi-asserted-by":"crossref","unstructured":"Yantorno RE, Carre DA, Coca-Prados M, Krupin T, and Civan MM. Whole cell patch clamping of ciliary epithelial cells during anisosmotic swelling. Am J Physiol Cell Physiol 262: C501\u2013C509, 1992.","DOI":"10.1152\/ajpcell.1992.262.2.C501"},{"key":"R55","doi-asserted-by":"crossref","unstructured":"Zhang JJ and Jacob TJ. Three different Cl\u2212 channels in the bovine ciliary epithelium activated by hypotonic stress. J Physiol 499: 379\u2013389, 1997.","DOI":"10.1113\/jphysiol.1997.sp021935"}],"container-title":["American Journal of Physiology-Cell Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/journals.physiology.org\/doi\/pdf\/10.1152\/ajpcell.00175.2004","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2024,6,17]],"date-time":"2024-06-17T18:39:30Z","timestamp":1718649570000},"score":1,"resource":{"primary":{"URL":"https:\/\/journals.physiology.org\/doi\/10.1152\/ajpcell.00175.2004"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2004,10]]},"references-count":55,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2004,10]]}},"alternative-id":["10.1152\/ajpcell.00175.2004"],"URL":"https:\/\/doi.org\/10.1152\/ajpcell.00175.2004","relation":{},"ISSN":["0363-6143","1522-1563"],"issn-type":[{"value":"0363-6143","type":"print"},{"value":"1522-1563","type":"electronic"}],"subject":[],"published":{"date-parts":[[2004,10]]}}}