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Klin Monbl Augenheilkd 2001; 218(5): 370-372
DOI: 10.1055/s-2001-15903
EXPERIMENTELLE STUDIE

Georg Thieme Verlag Stuttgart · New York

Cyclic AMP and anionic currents in porcine ciliary epithelium

cAMP-induzierte Anionenkanalaktivierung im Schweineziliarkörper Johannes  C. Fleischhauer1 , Jean-Louis Bény2 , Josef Flammer1 , Ivan  O. Haefliger1
  • 1 Laboratory of Ocular Pharmacology and Physiology, University Eye Clinic Basel, Mittlere Strasse 91, PO Box, CH-4012 Basel, Switzerland
  • 2 Department of Zoology and Animal Biology, Sciences III, Geneva University, Geneva, Switzerland
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Publication History

Publication Date:
31 December 2001 (online)

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Hintergrund Diese Pilot-Studie wurde durchgeführt, um zu testen, ob im isolierten Schweineziliarkörper die Erhöhung der intrazellulären cAMP-Konzentration eine Veränderung der Membranpermeabilität für Ionenströme bewirken kann.

Methoden Änderungen im Membranpotential, ausgelöst durch Forskolin (Adenylatzyklaseactivator; 10 μM; n=4) oder das cAMP-Analogon 8-Bromoadenosine 3′,5′-cyclic monophosphothioate (8-Br-cAMP; 30 μM; n=4) wurden mittels intrazellulärer Mikroelektroden gemessen. Der Effekt von Forskolin und 8-Br-cAMP wurde ebenfalls in An- oder Abwesenheit des Anionenkanalinhibitors Diisothiocyanato-stilbene, 2,2′-Disulfonsäure (DIDS; 1 mM; n=3) untersucht.

Resultate Forskolin und 8-Br-cAMP bewirkten beide eine signifikante (p < 0,001) Membranpotenzialdepolarisation (10,4 ± 2,0 mV und 11,7 ± 1,4 mV MW ± SEM). Die Depolarisationen induziert durch Forskolin und 8-Br-cAMP wurden durch DIDS (0,1 ± 1,0 mV und 0,7 ± 0,3 mV) gehemmt (p<0,001).

Schlussfolgerung Im isolierten Schweineziliarkörper führt die Erhöhung von cAMP zu einer Depolarisierung des Membranpotentials, ein Prozess, welcher Anionenkanäle zu involvieren scheint.

Abstract

Introduction To investigate whether in the ciliary epithelium of isolated porcine ciliary body cyclic 3′,5′ adenosine monophosphate (cAMP) activates transmembrane anionic currents.

Methods Changes in membrane potential induced either by the adenylcyclase activator forskolin (10 μM; n=4) or the stable membrane permeable cAMP analog 8-bromo-adenosine 3′,5′-cyclic monophosphothioate (8-br-cAMP; 30 μM; n=4) were measured with intracellular microelectrodes. The effect of the drugs were assessed in the absence or in the presence of the non-selective anionic channel/transporter inhibitor diisothiocyanatostilbene-2,2′ disulfonic acid (DIDS; 1 mM; n=4).

Results Significant (p < 0.001) membrane potential depolarization were induced by both forskolin (11.8 ± 0.3 mV) or 8-br-cAMP (9.3 ± 0.4 mV). In the presence of DIDS, a significant (p < 0.001) inhibition of the depolarization evoked by forskolin (0.9 ± 1.1 mV) and 8-bromo-cAMP (0.7 ± 0. 2 mV) was observed.

Conclusions In the ciliary epithelium of isolated porcine ciliary body cAMP induces membrane potential depolarization through a process that could involve anionic channels.

Schlüsselwörter:

Kammerwasserproduktion - Chloridkanäle - Elektrophysiologie - Augeninnendruck - Glaukom - transepithelialer Wassertransport

Key words

Aqueous humor formation - chloride channels - electrophysiology - intraocular pressure - glaucoma - transepithelial water transport

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