title: Effects of endothelin and calcium channel blockers on membrane voltage and intracellular calcium in cultured bovine trabecular meshwork cells.
abstract: The membrane voltage was measured in cultured bovine trabecular meshwork cells. External barium (Ba2+; 10 mM) evoked repetitive overshooting action potentials which were reversibly inhibited by 10(-6) M nifedipine but insensitive to tetrodotoxin (10(-5) M). In contrast, no action potentials could be induced in bovine corneal endothelial cells. The vasoactive peptide endothelin (10(-9)-10(-6) M) induced dose-dependent depolarizations. The intracellular calcium concentration measured by the fura-2 method increased after endothelin application. An initial peak was followed by a sustained plateau. The effect of endothelin on the membrane potential and intracellular calcium value is typical for smooth muscle cells showing a contractile response to the peptide. Recent studies have shown the contractility of bovine trabecular meshwork. We conclude that calcium-channel antagonists and endothelin may alter the aqueous humour outflow through the trabecular meshwork.
authors: Institut für klinische Physiologie, Klinikum Steglitz der Freien Universität Berlin, Federal Republic of Germany.
authors: A
authors: A
authors: Lepple-Wienhues
authors: F
authors: F
authors: Stahl
authors: D
authors: D
authors: Wunderling
authors: M
authors: M
authors: Wiederholt
mesh_terms: D000818:Animals; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002417:Cattle; D002478:Cells, Cultured; D016232:Endothelins / Q000494:pharmacology*; D016257:Fura-2 / Q000378:metabolism; D008564:Membrane Potentials / Q000187:drug effects*; D008839:Microelectrodes; D013779:Tetrodotoxin / Q000494:pharmacology; D014129:Trabecular Meshwork / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology
chemical_list: D002121:Calcium Channel Blockers; D016232:Endothelins; D001464:Barium; D013779:Tetrodotoxin; D002118:Calcium; D016257:Fura-2