Measurement of passive membrane parameters with whole-cell recording from neurons in the intact amphibian retina

P. A. Coleman, R. F. Miller

Research output: Contribution to journalArticle

93 Scopus citations

Abstract

Whole-cell recordings have been obtained from intact, photoactive retinal neurons using path-clamp electrodes in the amphibian superfused retina eyecup preparation. After removal of the vitreous humor from the surface of the retina, using a collagenase with low tryptic activity, high-resistance seals (1-10 GΩ) could be formed between the patch pipette and the cell membrane by applying mild suction to the pipette. Additional suction broke the membrane patch and provided continuity between the low-resistance pipette and the interior of the neuron. Measurements of input resistance and time constant were obtained from bipolar, amacrine, and ganglion cells. Assuming the membrane capacitance was 1 μF/cm2, time constant data were used to derive the specific membrane resistance. The average specific membrane resistance for the inner retinal neurons in our sample was 68,000 Ω · cm2. Analysis of the charging curve induced by a brief current pulse applied to the soma was used to analyze the average electrotonic length of dendrites. The charging curves of some ganglion cells were well represented by a single exponential, suggesting that they were essentially isopotential. The voltage decay along an equivalent cylinder model of a ganglion cell was calculated, using the experimentally obtained values of membrane resistance to compute decay of steady-state voltages as long the dendritic tree. The calculations indicate the with the high membrane resistance values implied by this study, the electrotonic length of dendritic cables were short, and there may be relatively little attenuation of the synaptic potentials irrespective of their location along the dendritic tree.

Original languageEnglish (US)
Pages (from-to)218-230
Number of pages13
JournalJournal of neurophysiology
Volume61
Issue number1
DOIs
StatePublished - Jan 1 1989

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