The role of dopamine in the life history of bivalves: a review

Dopamine is one of the best-known neurotransmitters found in most animals. Among the major roles that this mediator plays in many organisms is the regulation of motor skills, behavior, and feeding. Its localization in the central (CNS) and peripheral nervous systems (PNS) has been well studied mainly in vertebrate animals, but remains poorly understood in invertebrates such as mollusks of the class Bivalvia. Nevertheless, bivalves are of particular interest for their nervous system that has undergone a number of simplifications due to the sedentary lifestyle. As shown in the review, the key functions of dopamine have been retained in this group, with, however, a shift towards regulation of effector organs and physiological processes. The interaction between serotonin and dopamine, which regulates the degree of motor activity, nutrition, and locomotion, also deserves special consideration. There still remains a vast number of unresolved issues concerning the effects that dopamine exerts in the bivalve CNS, its role in the regulation of larval development and behavior of adults. This review summarizes the major known aspects of dopamine, including its localization and role in the life history of bivalves.