EFFECTS OF ODORANTS ON PIGMENT AGGREGATION AND CAMP IN FISH MELANOPHORES

Odor perception within olfactory neuroepithelium and pigment transloca tion within melanophores both seem to rely on a cAMP-based second mess enger system. From studies on cultured frog melanophores, Lerner et al . (Proc. Natl. Acad. Sci. USA 85:261-264, 1988) suggested that some as pect of odor perception may be mediated by a nonspecific mechanism who se signal is transduced by a cAMP-based second messenger system. In th e present study, odorants (beta-ionone, benzylaldehyde, cineole, cinna maldehyde, and octanol), which previously have been shown to stimulate formation of cAMP in the olfactory neuroepithelium, were investigated for possible pigment dispersing and cAMP-increasing effects. Pretreat ment of fish melanophores with the adenylate cyclase activator forskol in (1 mu M) resulted in an approximately 300% increase in cAMP and an almost complete blockage of noradrenaline-induced pigment aggregation. However, none of the tested odorants were able to increase the cAMP l evel and only cinnaldehyde and beta-ionone were found to have any pigm ent dispersing activity.