Caracterització electrofisiològica del canal de K+ dalta conductància dependent de Ca2+ (BKCa) a la cèllula trabecularmodulació per lstretch i la hipòxia

Abstract

SUBJECT: Electrophysiological characterization of a large conductance Ca2+-activated K+ channel (BKCa) in trabecular meshwork cells: modulation by membrane stretch and hypoxia TEXT: The understanding of the physiology of the trabecular meshwork has advanced in the last few years, however few ionic channels have been characterized in this tissue. The large conductance Ca2+-activated K+ channel (BKCa) has been identified in the trabecular meshwork cells but its function is still unknown. BKCa channel is voltage dependent and its activity is modulated by intracellular calcium concentration ([Ca2+]i), with different functions depending on the cell type. In excitable cells it controls neuronal excitability, participates in neurotransmitter release and modulates contractile tone in vascular smooth muscle. In non-excitable cells it has been described its participation in cell volume regulation and its modulatory effect on different substances that mobilize [Ca2+]i. Besides [Ca2+]I, other substances such as cGMP or nitric oxide modulate the activity of BKCa channel in the trabecular meshwork. In other tissues, BKCa channel has shown mechanosensitive properties and it has also been described how its activity is modified by low PO2 values (hypoxia). Since trabecular meshwork cells are subjected to intraocular pressure and that aqueous humor contained in the anterior chamber presents PO2 values lower than other tissues, it is important to study the effects of these modulators on BKCa channel activity which will have a direct effect on the physiology of the trabecular meshwork."