Washington, September 29 University of Texas at Austin researchers have discovered that 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.
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, according to Harold Zakon, professor of neurobiology.
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," said 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," he added.arkham said that the rapidity of the action is particularly stunning.
"This is happening within a matter of two to three minutes," he said. "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," he added.
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.
When the fish are inactive, they remove the sodium channels from the cell membranes to reduce the intensity of the electric impulse. (ANI)
