Host: The Physiological Society of Japan
Male prairie voles (Microtus ochrogaster) display mating-induced pair bonding, demonstrated by a preference for a familiar partner versus a conspecific stranger (partner preference) and aggression towards a stranger (selective aggression). Therefore, this species provides an excellent opportunity to study the neurobiology of social attachment. In a series of experiments, we systematically examined the role of dopamine (DA) in the nucleus accumbens (NAcc) in the regulation of pair bonding in male prairie voles. The vole NAcc contained DA terminals and receptors, and mating increased DA release/turnover. Intra-NAcc activation of D2-type, but not D1-type, DA receptors facilitated partner preference formation whereas blockade of D2-type, but not D1-type, receptors inhibited this behavior induced by mating or by D2 receptor activation. This receptor-specific effect of DA on partner preference formation was further confirmed by manipulations of the cAMP signaling transduction pathway in the NAcc. In addition, two weeks of pair bonding resulted in an increase in the density of D1-type receptors in the NAcc in males that displayed selective aggression. Blockade of these receptors blocked selective aggression. Together, these data demonstrate that NAcc DA regulates pair bond formation and maintenance in a region- and receptor-specific manner. We also examined the interaction of DA with other neurotransmitter systems, including vasopressin and oxytocin, and our data illustrate a neural circuit important in pair bonding. (supported by NIH grants from NIMH and NIDA) [J Physiol Sci. 2008;58 Suppl:S2]
