Light Response of a Giant Aplysia Neuron
Illumination of an Aplysia giant neuron evokes a membrane hyperpolarization which is associated with a membrane conductance increase of 15%. The light response is best elicited at 490 nM: the neuron also has an absorption peak at this wavelength. At the resting potential (-50 to -60 mV) illuminatio...
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| Format: | Online |
| Language: | English |
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The Rockefeller University Press
1973
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| Online Access: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2226119/ |
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pubmed-2226119 |
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oai_dc |
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pubmed-22261192008-04-23 Light Response of a Giant Aplysia Neuron Brown, Arthur M. Brown, H. Mack Article Illumination of an Aplysia giant neuron evokes a membrane hyperpolarization which is associated with a membrane conductance increase of 15%. The light response is best elicited at 490 nM: the neuron also has an absorption peak at this wavelength. At the resting potential (-50 to -60 mV) illumination evokes an outward current in a voltage-clamped cell. This current reverses sign very close to E K calculated from direct measurements of internal and external K+ activity. Increases in external K+ concentration shift the reversal potential of the light-evoked response by the same amount as the change in E K. Decreases in external Na+ or Cl- do not affect the response. Therefore, the response is attributed to an increase in K+ conductance. Pressure injection of Ca2+ into this neuron also hyperpolarizes the cell membrane. This effect is also due largely to an increase in K+ conductance. The light response after Ca2+ injection does not appear to be altered. Pressure injection of EGTA abolished or greatly reduced the light response. The effect was reversible. We suggest that light acts upon a single pigment in this neuron, releasing Ca2+ which in turn increases K+ conductance, thereby hyperpolarizing the neuronal membrane. The Rockefeller University Press 1973-09-01 /pmc/articles/PMC2226119/ /pubmed/4730667 Text en Copyright © 1973 by The Rockefeller University Press This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
| repository_type |
Open Access Journal |
| institution_category |
Foreign Institution |
| institution |
US National Center for Biotechnology Information |
| building |
NCBI PubMed |
| collection |
Online Access |
| language |
English |
| format |
Online |
| author |
Brown, Arthur M. Brown, H. Mack |
| spellingShingle |
Brown, Arthur M. Brown, H. Mack Light Response of a Giant Aplysia Neuron |
| author_facet |
Brown, Arthur M. Brown, H. Mack |
| author_sort |
Brown, Arthur M. |
| title |
Light Response of a Giant Aplysia Neuron |
| title_short |
Light Response of a Giant Aplysia Neuron |
| title_full |
Light Response of a Giant Aplysia Neuron |
| title_fullStr |
Light Response of a Giant Aplysia Neuron |
| title_full_unstemmed |
Light Response of a Giant Aplysia Neuron |
| title_sort |
light response of a giant aplysia neuron |
| description |
Illumination of an Aplysia giant neuron evokes a membrane hyperpolarization which is associated with a membrane conductance increase of 15%. The light response is best elicited at 490 nM: the neuron also has an absorption peak at this wavelength. At the resting potential (-50 to -60 mV) illumination evokes an outward current in a voltage-clamped cell. This current reverses sign very close to E
K calculated from direct measurements of internal and external K+ activity. Increases in external K+ concentration shift the reversal potential of the light-evoked response by the same amount as the change in E
K. Decreases in external Na+ or Cl- do not affect the response. Therefore, the response is attributed to an increase in K+ conductance. Pressure injection of Ca2+ into this neuron also hyperpolarizes the cell membrane. This effect is also due largely to an increase in K+ conductance. The light response after Ca2+ injection does not appear to be altered. Pressure injection of EGTA abolished or greatly reduced the light response. The effect was reversible. We suggest that light acts upon a single pigment in this neuron, releasing Ca2+ which in turn increases K+ conductance, thereby hyperpolarizing the neuronal membrane. |
| publisher |
The Rockefeller University Press |
| publishDate |
1973 |
| url |
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2226119/ |
| _version_ |
1611436997738496000 |