Featured Research

from universities, journals, and other organizations

Electric Fish Plug In To Communicate

Date:
September 29, 2009
Source:
University of Texas at Austin
Summary:
Just as people plug in to computers, smart phones and electric outlets to communicate, electric fish communicate by quickly plugging special channels into their cells to generate electrical impulses, researchers have discovered.

From the PLoS Biology paper: Electric fish generate electric organ discharges (EODs) by the simultaneous action potentials (APs) of excitable cells in the electric organ. (A) The EOD is produced by the coordinated APs of the electric organ cells, called electrocytes. A medullary pacemaker nucleus controls the electrocyte APs via spinal electromotor neurons which innervate the electrocytes. (B) Electrocytes are innervated on the posterior end of the cell, where the spinal nerve forms a large cholinergic synapse. The electrically excitable region of the cell membrane, populated by Na+ and K+ channels, is localized to the posterior most region of the cell, extending approximately 150 m toward the anterior of the cell. The remainder of the cell membrane is electrically passive. APs in the electrocytes cause current to move along the rostral-caudal body axis and out into the surrounding water. (C) A section of electric organ from the tail, with skin removed to expose the electrocytes, which are densely packed within the electric organ. A single electrocyte is outlined in red. (D) The EOD waveform recorded from S. macrurus is a sinusoidal wave emitted at a steady frequency by each fish. The EOD frequency among fish has a range of approximately 70 to 150 Hz.
Credit: Michael R. Markham, M. Lynne McAnelly, Philip K. Stoddard, Harold H. Zakon. Circadian and Social Cues Regulate Ion Channel Trafficking. PLoS Biology, 2009;7(9): e1000203 DOI: 10.1371/journal.pbio.1000203

Just as people plug in to computers, smart phones and electric outlets to communicate, electric fish communicate by quickly plugging special channels into their cells to generate electrical impulses, University of Texas at Austin researchers have discovered.

The fish generate electric fields to navigate, fight and attract mates in murky streams and rivers throughout Central and South America. They do so at night, while trying to avoid predators such as catfish that sense the electric fields.

Generating electricity is costly (ask any homeowner paying for air conditioning during a hot summer), and the fish are using a dimmer switch to save energy by turning their electrical signals up and down, says Harold Zakon, professor of neurobiology.

Zakon, Michael Markham and Lynne McAnelly published their findings on the electric fish in PLoS Biology on Sept. 29.

They found that the dimmer switch comes in the form of sodium channels the fish insert and remove from the membranes of special cells, called electrocytes, within their electric organs. When more sodium channels are in the cell membrane, the electric impulse emitted by the electric organ is greater.

The scientists also show that the process is under the control of hormones. And it is maintained through a day-night circadian rhythm and can change rapidly during social encounters.

"For a vertebrate animal, this is the first account that brings the whole system together from the behavior down to the rapid insertion of channels and in such an ecologically meaningful way," says Markham, a research scientist in the Zakon laboratory. "This is part of the animal's every day activity and it is being regulated very tightly by a low level molecular change."

Markham says the rapidity of the action is particularly stunning.

"This is happening within a matter of two to three minutes," he says. "The machinery is there to make this dramatic remodeling of the cell, and it does so within minutes from the time that some sort of stimulus is introduced in the environment."

The electric impulse can likely be produced so quickly because a reservoir of sodium channels is sitting in storage in the electric cells. When serotonin is released in the fish brain, it initiates the release of adrenocorticotropic hormone from the pituitary gland. This gooses the mechanism that puts more sodium channels in the membrane.

"It's kind of like stepping on the gas in a car sitting there with its engine already running," says Zakon.

When the fish are inactive, they remove the sodium channels from the cell membranes to reduce the intensity of the electric impulse.

The electrocytes in the fishes' electric organ are made of modified muscle cells. This is significant because the vertebrate heart, which is also a muscle, can also add sodium channels to its cells to help it pump faster. The electric organ and heart are discharging constantly, and both organs are energetically costly.

"One big question for us in the future is, did this mechanism evolve once a long time ago or is this a case of convergent evolution, where the vertebrate heart evolved the ability to traffic these channels and then the electric organ evolved the same ability independently?" says Zakon.

McAnelly was a research scientist in the Zakon lab and is director of the Women In Natural Sciences program at The University of Texas at Austin. A fourth collaborator on the research, Philip Stoddard, is a professor at Florida International University.


Story Source:

The above story is based on materials provided by University of Texas at Austin. Note: Materials may be edited for content and length.


Journal Reference:

  1. Michael R. Markham, M. Lynne McAnelly, Philip K. Stoddard, Harold H. Zakon. Circadian and Social Cues Regulate Ion Channel Trafficking. PLoS Biology, 2009;7(9): e1000203 DOI: 10.1371/journal.pbio.1000203

Cite This Page:

University of Texas at Austin. "Electric Fish Plug In To Communicate." ScienceDaily. ScienceDaily, 29 September 2009. <www.sciencedaily.com/releases/2009/09/090928201849.htm>.
University of Texas at Austin. (2009, September 29). Electric Fish Plug In To Communicate. ScienceDaily. Retrieved April 23, 2014 from www.sciencedaily.com/releases/2009/09/090928201849.htm
University of Texas at Austin. "Electric Fish Plug In To Communicate." ScienceDaily. www.sciencedaily.com/releases/2009/09/090928201849.htm (accessed April 23, 2014).

Share This



More Matter & Energy News

Wednesday, April 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Air Force: $4.2B Saved from Grounding A-10s

Air Force: $4.2B Saved from Grounding A-10s

AP (Apr. 23, 2014) Speaking about the future of the United States Air Force, Chief of Staff Gen. Mark Welsh says the choice to divest the A-10 fleet was logical and least impactful. (April 23) Video provided by AP
Powered by NewsLook.com
Is North Korea Planning Nuclear Test #4?

Is North Korea Planning Nuclear Test #4?

Newsy (Apr. 22, 2014) South Korean officials say North Korea is preparing to conduct another nuclear test, but is Pyongyang just bluffing this time? Video provided by Newsy
Powered by NewsLook.com
China Falls for 4x4s at Beijing Auto Show

China Falls for 4x4s at Beijing Auto Show

AFP (Apr. 22, 2014) The urban 4x4 is the latest must-have for Chinese drivers, whose conversion to the cult of the SUV is the talking point of this year's Beijing auto show. Duration: 00:40 Video provided by AFP
Powered by NewsLook.com
Hagel Gets Preview of New High-Tech Projects

Hagel Gets Preview of New High-Tech Projects

AP (Apr. 22, 2014) Defense Secretary Chuck Hagel is given hands-on demonstrations Tuesday of some of the newest research from DARPA _ the military's Defense Advanced Research Projects Agency program. (April 22) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins