Abstract
Treatment of Fundulus melanophores with adenosine 3′,5′‐monophosphate (cyclic AMP) is followed by reversible melanin dispersion in these cells. Adenosine 3′‐monophosphate and adenosine 5′‐monophosphate both have a similar, but weaker dispersing action. In addition, adenosine 5′‐monophosphate also has a melanin aggregating effect. These results are interpreted to mean that nerve transmitters may act by controlling the level of cyclic AMP within the Fundulus melanophore.