SEROTONIN INVOLVEMENT IN LARVAL SETTLEMENT OF THE BARNACLE, BALANUS AMPHITRITE

Following our previous report (Yamamoto et al. [1995] Zool. Sci., 12:3 91-396) in which we demonstrated that protein kinase C (PKC) plays an important role in larval metamorphosis of the barnacle Balanus amphitr ite, we examined the effects of a range of neurotransmitters, includin g serotonin (5-hydroxytryptamine), epinephrine, and norepinephrine on cyprid settlement and metamorphosis. Serotonin induced pronounced larv al settlement. Furthermore, settlement was inhibited by neurotransmitt er uptake blockers, such as amitriptyline, imipramine, and desipramine , in a concentration-dependent manner. Cyprids exposed to these uptake blockers metamorphosed without settling on substrata. These results s uggest that serotonin is involved in larval Settlement. (C) 1996 Wiley -Liss, Inc.