HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Tachibana, M Search for Related Content PubMed PubMed Citation Articles by Tachibana, M

1. Solitary horizontal cells were obtained by dissociating the adult goldfish retina using the enzyme papain. The cells were identified on morphological grounds and could be kept in culture for over a week. 2. Solitary horizontal cells, penetrated with micro-electrodes, had resting potentials of about -75 mV in normal solution. When external K+ concentration was changed, the membrane potential varied from EK calculated from the Nernst equation. 3. All solitary horizontal cells tested showed an action potential in response to superthreshold depolarizing current pulses. The action potential had an overshoot of about +20 mV and a plateau potential lasting for several seconds. 4. The action potential appeared to be Ca-dependent for the following reasons: (a) TTX or low [Na+] did not affect the action potential, (b) Sr2+, Ba2+ or high [Ca2+] enhanced the action potential, while (c) Co2+ or high [Mg2+] blocked it. No regenerative activity has been observed in horizontal cells in the retina but it is possible that the regenerative mechanism is suppressed normally. 5. A role for K+ was indicated by an increase in the duration and amplitude of the action potential on the application of tetraethylammonium. 6. The steady-state current--voltage (I--V) curve, measured by applying constant current pulses, was S-shaped (current on the abscissa) and composed of inward- and outward-going rectifying regions and a transitional region between them. A similar non-linear I--V relationship has been reported in vivo. 7. The transitional region was characterized by a sudden potential jump and hysteresis, suggesting the presence of a 'negative resistance'. This potential jump appeared not to be produced by the Ca-conductance mechanism mentioned above, since similar jumps were observed in the presence of Co2+.

This article has been cited by other articles:

				A. V. Dmitriev and S. C. Mangel Electrical Feedback in the Cone Pedicle: A Computational Analysis J Neurophysiol, March 1, 2006; 95(3): 1419 - 1427. [Abstract] [Full Text] [PDF]

				Y. Hayashida and T. Yagi On the Interaction Between Voltage-Gated Conductances and Ca2+ Regulation Mechanisms in Retinal Horizontal Cells J Neurophysiol, January 1, 2002; 87(1): 172 - 182. [Abstract] [Full Text] [PDF]