Voltage- and GABA-evoked currents from Müller glial cells of the baboon retina.
The electrophysiological features of isolated baboon Müller cells was investigated using the whole-cell voltage-clamp technique. Application of depolarizing voltage steps evoked transient inward and delayed outward currents. The transient currents disappeared when extracellular Na+ was replaced by choline+ and were substantially decreased by application of tetrodotoxin (1 microM). The outward currents were strongly diminished by extracellular Ba2+ (1 mM), and the hyperpolarization-generated inward currents disappeared following application of Ba2+. The recently described gamma-aminobutyric acid A (GABAA) receptor currents were increased by flunitrazepam, nordiazepam, pentobarbital and Zn2+, as well as by the inverse agonist DMCM. These results suggest that the baboon Müller cells possess the same voltage-dependent current pattern as those from other species, e.g. humans, whereas their GABAA receptors react in an uncharacteristic manner to DMCM and Zn2+, when compared with neuronal GABAA receptors.
Reichelt
W
W
Paul-Flechsig-Institute for Brain Research, Department of Neurophysiology, University of Leipzig, Germany.
Hernandez
M
M
Damian
R T
RT
Kisaalita
W S
WS
Jordan
B L
BL
D000818:Animals; D009457:Neuroglia / Q000187:drug effects*; D010215:Papio; D018408:Patch-Clamp Techniques; D012160:Retina / Q000187:drug effects / Q000502:physiology*; D005680:gamma-Aminobutyric Acid / Q000494:pharmacology*
D005680:gamma-Aminobutyric Acid