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Voltage‐gated Currents in Rabbit Retinal Astrocytes
Author(s) -
Clark Beverley A.,
Mobbs Peter
Publication year - 1994
Publication title -
european journal of neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.346
H-Index - 206
eISSN - 1460-9568
pISSN - 0953-816X
DOI - 10.1111/j.1460-9568.1994.tb01002.x
Subject(s) - retina , biophysics , tetraethylammonium , depolarization , membrane potential , retinal , tetrodotoxin , chemistry , patch clamp , electrophysiology , 4 aminopyridine , voltage clamp , potassium channel , anatomy , neuroscience , potassium , biology , biochemistry , organic chemistry
The voltage‐gated currents of the astrocytes associated with the retinal capillaries of the rabbit retina were studied using whole‐cell patch clamp recording. The resting potential of these cells was −70 ± 4.8 mV (mean ± SEM; n = 54), and the input resistance and cell capacitance were 558 ± 3.6 MΩ and 19.5 ± 1.8 pF respectively. Depolarization to potentials positive to −50 mV evoked rapidly activating inward and outward currents. The inward current was transient, eliminated by substitution of choline for Na + in the bathing solution, and reduced by 50% in the presence of 1 μM tetrodotoxin. The time‐to‐peak of the Na + current was more than twice that for the Na + current found in retinal neurons. The glial Na + current was half‐inactivated at −55 mV. A transient component of the outward K + current was blocked by external 4‐aminopyridine while a more sustained component was blocked by external tetraethylammonium. At potentials between −150 and −50 mV the membrane behaved Ohmically. Voltage‐gated currents in retinal astrocytes recorded in situ appear qualitatively similar to those described for some glial cells in vitro.