Cyclic nucleotide action is mediated through adenosine receptors in damselfish motile iridophores

Abstract 1. 1. Effects of cyclic nucleotides on motile iridophores were examined in the blue damselfish, Chrysiptera cyanea . 2. 2. All of the cyclic nucleotides tested, i.e. cAMP, 2',3'-cAMP and cGMP, accelerated the clearing response of the cells even at concentrations of 10 −5 or 10 −4 M. 3. 3. The action of these nucleotides was effectively antagonized by methylxanthines. 4. 4. These results suggest that the effect of cyclic nucleotides on damselfish iridophores is mediated by adenosine receptors in a similar fashion to the action of adenosine.