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Effects of Melatonin, Serotonin, and Naloxone on Aggression in Isolated Cichlid Fish ( Aequidens pulcher )
Author(s) -
Munro A. D.
Publication year - 1986
Publication title -
journal of pineal research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.881
H-Index - 131
eISSN - 1600-079X
pISSN - 0742-3098
DOI - 10.1111/j.1600-079x.1986.tb00748.x
Subject(s) - melatonin , serotonin , (+) naloxone , medicine , endocrinology , aggression , 5 ht receptor , cichlid , fish <actinopterygii> , biology , opioid , psychiatry , receptor , fishery
Intracranial injections of 10 μg melatonin, with or without 4 μg naloxone, result in reduced aggressive responsiveness by the cichlid fish Aequidens pulcher to a mirror presented 20 min later. Naloxone, when administered on its own, had no behavioral effect. Intracranial injections of 25 μg serotonin‐creatinine sulphate complex (5HT‐CS) also reduced aggression. 5HT‐CS's action was abolished if the injection included 10 μg S‐adenosyl homocysteine (SAH), which inhibits the conversion of serotonin to melatonin. This suggests that the behavioral action of 5HT‐CS may be mediated by its conversion to melatonin. There is inconclusive evidence to suggest that 37.5 μg 5HT‐CS, administered in conjunction with 10 μg SAH, may reduce aggressiveness; injection of 50 μg 5HT‐CS, with or without 10 μg SAH, induced a pronounced escape behavior which precluded any measurement of aggressiveness in the fish.