title: Screening of gap junction antagonists on dye coupling in the rabbit retina.
abstract: Many cell types in the retina are coupled via gap junctions and so there is a pressing need for a potent and reversible gap junction antagonist. We screened a series of potential gap junction antagonists by evaluating their effects on dye coupling in the network of A-type horizontal cells. We evaluated the following compounds: meclofenamic acid (MFA), mefloquine, 2-aminoethyldiphenyl borate (2-APB), 18-alpha-glycyrrhetinic acid, 18-beta-glycyrrhetinic acid (18-beta-GA), retinoic acid, flufenamic acid, niflumic acid, and carbenoxolone. The efficacy of each drug was determined by measuring the diffusion coefficient for Neurobiotin (Mills & Massey, 1998). MFA, 18-beta-GA, 2-APB and mefloquine were the most effective antagonists, completely eliminating A-type horizontal cell coupling at a concentration of 200 muM. Niflumic acid, flufenamic acid, and carbenoxolone were less potent. Additionally, carbenoxolone was difficult to wash out and also may be harmful, as the retina became opaque and swollen. MFA, 18-beta-GA, 2-APB and mefloquine also blocked coupling in B-type horizontal cells and AII amacrine cells. Because these cell types express different connexins, this suggests that the antagonists were relatively non-selective across several different types of gap junction. It should be emphasized that MFA was water-soluble and its effects on dye coupling were easily reversible. In contrast, the other gap junction antagonists, except carbenoxolone, required DMSO to make stock solutions and were difficult to wash out of the preparation at the doses required to block coupling in A-type HCs. The combination of potency, water solubility and reversibility suggest that MFA may be a useful compound to manipulate gap junction coupling.
authors: Department of Ophthalmology and Visual Science, University of Texas Medical School at Houston, Houston, Texas 77030, USA.
authors: Feng
authors: F
authors: Pan
authors: Stephen L
authors: SL
authors: Mills
authors: Stephen C
authors: SC
authors: Massey
mesh_terms: D000465:Algorithms; D000818:Animals; D001710:Biotin / Q000031:analogs & derivatives / Q000378:metabolism; D001896:Boron Compounds / Q000494:pharmacology; D004396:Coloring Agents; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D004058:Diffusion; D004353:Drug Evaluation, Preclinical; D005260:Female; D017629:Gap Junctions / Q000187:drug effects*; D006034:Glycyrrhetinic Acid / Q000494:pharmacology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D008469:Meclofenamic Acid / Q000494:pharmacology; D015767:Mefloquine / Q000494:pharmacology; D018613:Microscopy, Confocal; D009415:Nerve Net / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D011817:Rabbits; D012160:Retina / Q000166:cytology / Q000187:drug effects*
chemical_list: D001896:Boron Compounds; D004396:Coloring Agents; D016861:Cyclooxygenase Inhibitors; C070614:neurobiotin; D008469:Meclofenamic Acid; D001710:Biotin; C035757:diphenylborate; D006034:Glycyrrhetinic Acid; D015767:Mefloquine
references: J Neurosci. 1982 Oct;2(10):1486-93
references: 6181232
references: J Pharmacol Exp Ther. 2006 Dec;319(3):1452-8
references: 16985167
references: J Neurocytol. 1990 Oct;19(5):731-6
references: 1706416
references: Vis Neurosci. 1994 May-Jun;11(3):501-17
references: 8038125
references: Vis Neurosci. 1994 May-Jun;11(3):549-60
references: 7518689
references: Nature. 1995 Oct 26;377(6551):734-7
references: 7477263
references: J Comp Neurol. 1996 Feb 26;366(1):15-33
references: 8866843
references: Proc Natl Acad Sci U S A. 2001 Sep 11;98(19):10942-7
references: 11535816
references: J Membr Biol. 2002 Jan 15;185(2):93-102
references: 11891568
references: Biol Chem. 2002 May;383(5):725-37
references: 12108537
references: Neuron. 2002 Nov 14;36(4):703-12
references: 12441058
references: Nat Rev Mol Cell Biol. 2003 Apr;4(4):285-94
references: 12671651
references: J Vis. 2002;2(4):272-92
references: 12678578
references: Mol Pharmacol. 2003 Jun;63(6):1389-97
references: 12761350
references: J Neurosci. 2003 Nov 12;23(32):10249-57
references: 14614083
references: Vis Neurosci. 2003 Jul-Aug;20(4):429-35
references: 14658771
references: Cell Commun Adhes. 2003 Jul-Dec;10(4-6):425-30
references: 14681052
references: J Comp Neurol. 2004 Feb 23;470(1):1-12
references: 14755521
references: J Neurosci. 2004 Mar 31;24(13):3325-34
references: 15056712
references: Eur J Neurosci. 2004 May;19(10):2633-40
references: 15147297
references: J Neurosci. 2004 Jun 16;24(24):5632-42
references: 15201336
references: J Neurophysiol. 2004 Aug;92(2):1252-6
references: 15028741
references: Proc Natl Acad Sci U S A. 2004 Aug 17;101(33):12364-9
references: 15297615
references: J Neurosci. 1999 Nov 15;19(22):9848-55
references: 10559394
references: Vis Neurosci. 1999 Sep-Oct;16(5):811-8
references: 10580717
references: Vis Neurosci. 1999 Nov-Dec;16(6):1181-9
references: 10614597
references: J Comp Neurol. 2000 Sep 18;425(2):193-201
references: 10954839
references: J Neurosci. 2000 Nov 15;20(22):8629-36
references: 11069972
references: J Neurosci. 2001 Jan 1;21(1):230-9
references: 11150340
references: J Comp Neurol. 2001 Jul 30;436(3):336-50
references: 11438934
references: Mol Pharmacol. 2001 Sep;60(3):541-52
references: 11502886
references: J Pharmacol Exp Ther. 2001 Sep;298(3):1033-41
references: 11504800
references: Proc R Soc Lond B Biol Sci. 1978 Dec 18;203(1152):229-45
references: 84387
references: Proc R Soc Lond B Biol Sci. 1978 Dec 18;203(1152):247-67
references: 84388
references: Vis Neurosci. 1997 May-Jun;14(3):565-76
references: 9194323
references: Neurosci Lett. 1998 Feb 20;242(3):163-6
references: 9530931
references: Vis Neurosci. 1998 Jul-Aug;15(4):765-77
references: 9682877
references: J Neurosci. 1998 Dec 15;18(24):10594-602
references: 9852595
references: J Physiol. 1999 Jun 15;517 ( Pt 3):673-89
references: 10358109
references: J Neurosci. 2005 Jan 19;25(3):566-76
references: 15659592
references: Biophys J. 2005 Mar;88(3):1725-39
references: 15596513
references: J Neurophysiol. 2005 Mar;93(3):1476-85
references: 15525810
references: Nat Rev Neurosci. 2005 Mar;6(3):191-200
references: 15738956
references: Mol Pharmacol. 2005 Apr;67(4):1053-66
references: 15598972
references: J Neurosci. 2005 Jul 13;25(28):6696-701
references: 16014731
references: J Comp Neurol. 2005 Sep 12;490(1):29-39
references: 16041717
references: Proc Natl Acad Sci U S A. 2005 Sep 13;102(37):13313-8
references: 16150718
references: J Comp Neurol. 2005 Nov 7;492(1):66-77
references: 16175559
references: Vision Res. 2006 Feb;46(4):467-74
references: 16023694
references: J Neurosci. 2006 Feb 8;26(6):1759-66
references: 16467524
references: J Neurosci. 2006 Apr 19;26(16):4206-15
references: 16624941
references: Eur J Neurosci. 2006 Sep;24(6):1675-86
references: 17004931
references: J Neurosci. 2006 Nov 8;26(45):11624-36
references: 17093084
references: J Membr Biol. 1985;84(3):269-83
references: 4032457