On postnatal day eight, prairie vole pups were randomly assigned a treatment of 1 mg/kg SKF38393 (D1 agonist), quinpirole (D2 agonist), SCH23390 (D1 antagonist), eticlopride (D2 antagonist), or saline vehicle. As adults, females treated with eticlopride exhibited reduced anxiety-like behavior in an elevated plus maze and a reduction in infanticidal behavior. These behavioral effects were not seen in males. These data demonstrate that a single exposure to a D2 antagonist during development can have persistent, sex-specific effects on behavior into adulthood.Keywords prairie vole; anxiety; alloparenting; dopamine Prairie voles (Microtus ochrogaster) are microtine rodents that are characterized by affiliative social behaviors including selective partner preferences, biparental care, and cooperative breeding [15]. The early endocrine and neuroendocrine environments play a critical role in the development of these species-specific behaviors. A number of hormones that play a key role in the expression of adult prairie vole social behavior have also been shown to play a developmental role as well (corticosterone: [30]; testosterone: [30]; oxytocin: [5][6][7][8]14,29] arginine vasopressin: [37]).Recently dopamine has emerged as a key neurotransmitter in the regulation of prairie vole pair-bonding [3,4,17,23,39]. Prairie voles have been shown to be developmentally sensitive to early exposure to amphetamine, a dopamine reuptake inhibitor [28]. Daily administration of amphetamine over PND 13-15 changed social affiliation levels in adult prairie voles. Both male and female subjects given high doses of amphetamine spent more time alone than saline controls. However, low dose exposed animals showed sexually dimorphic responses to treatment when compared to controls: males spent more time alone, whereas females spent more time affiliating with the stranger. These data indicate that the developing Please send correspondence to: Caroline M. Hostetler, Dept. of Psychology, One Shields Ave., University of California, Davis, CA 95616. Phone: 530-220-3142, Fax: 530-752-2087, chostetler@ucdavis.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. We therefore hypothesized that alterations in dopamine receptor activity at PND8 may have potential long-term effects on behavior. Given that dopamine has been associated with anxiety-related behaviors and maternal behavior in a number of other previously studied species, we also hypothesized that behavior in an elevated plus maze and alloparental responsiveness in prairie voles are influenced by dopaminergic activity. This study was designed...

The monogamous prairie vole displays developmental sensitivity to early pharmacological manipulation in a number of species-typical social behaviors. The long-term consequences of altering the neonatal dopamine system are not well characterized. The present study examined whether early manipulation of the dopamine system, a known mediator of adult prairie vole social behavior, during neonatal development would affect adult aggressive and attachment behaviors. Eight-day-old pups were given a single treatment with either 1mg/kg SKF38393 (D1 agonist), quinpirole (D2 agonist), SCH23390 (D1 antagonist), eticlopride (D2 antagonist), or saline vehicle. As adults, subjects received tests for intrasexual aggression and partner preference. Activation of D1-like receptors in pups impaired partner preference formation but had no effect on aggression. Other neonatal treatments had no effect on their behavior as adults. To determine if D1 activation in pups induced changes in dopamine receptor expression, we performed autoradiography on striatal tissue from a second cohort of saline and SKF38393 treated animals. Although sex differences were observed, we found no treatment differences in D1 or D2 receptor binding in any striatal sub-region. This study shows that exposure to a single early pharmacological alteration of dopamine receptor activity may have long-term effects on the social behavior of prairie voles.