Continuous recording of erythrophore membrane potential during change of stage inOcypode pallidula (Crustacea)
✍ Scribed by Hayashi, J. H. ;Cooke, I. M.
- Book ID
- 102893486
- Publisher
- John Wiley and Sons
- Year
- 1978
- Tongue
- English
- Weight
- 576 KB
- Volume
- 204
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
Intracellular recordings of membrane potential were obtained from the central region of Erythrophore of the ghost crab (Ocypode pallidula) in all stages of aggregation. Stable membrane potentials were recorded from 58 cells. The potential was unrelated to stage. The average value was −59.0 ± 5.86 mV; the mode was −60 mV. The mode analyzed by stage was also −60mV. Fourteen erythrophores were continuously recorded during one or more complete cycles of aggregation, in response to erythrophore concentrating hormone (applied as an eyestalk extract), and subsequent reexpansion during continued saline perfusion. Membrane potential varied by less than 3 mV from its initial value and did so in a random manner. Injection of hyperpolarizing or depolarizing currents of up to 10^−8^ A for periods as long as ten minutes caused no visible responses. Current‐voltage relations, observed for six cells, were linear over the range tested (± 20 mV) and provided estimates of input resistance which averaged 18 megohms. A marked increase in electrode voltage noise, from less than 0.5 mV to as much as 2 mV, upon penetration of chromatophores was consistently observed. Changes of membrane potential are not involved in the responses of erythrophores to neurohormones nor associated with migration of pigment granules. Membrane potentials do not vary with the state of aggregation of these cells.