FRIDAY, May 2, 2003 (HealthDayNews) -- The first proof that fish feel pain is outlined in a study by University of Edinburgh and Roslin Institute researchers that appears in the journal Proceedings B.
While it's already been established that mammals and birds can feel pain, the question of whether fish feel pain has remained unanswered.
The researchers tested the responses of anesthetized rainbow trout to various mechanical, thermal and chemical stimuli. They found 58 receptors in the face and head of the rainbow trout that responded to at least one of the stimuli.
The study says that 22 of those receptors could be classified as nocieptors -- receptors that respond to tissue-damaging stimuli.
The researchers determined that not only are there nervous system receptors in the head and face of the trout that respond to damaging stimuli, but short-acting noxious substances such as bee venom produce significant behavioral and physiological changes in the fish. These occur over a prolonged period similar to that observed in higher mammals.
"Our research demonstrates nocireception and suggests that noxious stimulation in the rainbow trout had adverse behavioral and physiological effects. This fulfills the criteria for animal pain," researcher Dr. Lynne Sneddon says in a news release.
More information
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