1Laboratory of Reproductive Ecology and Environmental Toxicology, Department of Anthropology, Emory University, 2Center for Behavioral Neuroscience, Yerkes National Primate Research Center, 3Department of Psychiatry and Behavioral Sciences, Emory University School of Medicine, 4Non-Human Primate Research Core, National Institute of Mental Health
Friday 4:00-4:15, Ballroom B
The behavioral consequences of early maternal deprivation often evoke human psychopathologies and dementias involving a defective neurotransmission of dopamine. Therefore, we investigated the impact of maternal deprivation on brain dopaminergic pathways during three multidisciplinary and comparative studies of nursery/peer-reared (NR, n=6) and mother-reared (MR, n=6), male, juvenile rhesus monkeys. First, basic neuroendocrine functioning was determined through cerebrospinal fluid (CSF) samples of serotonin, dopamine, and the dopamine metabolites homovanillic acid (HVA), and 3,4-dihydroxyphenylacetic acid (DOPAC). Then, to measure dopaminergic tone, serum prolactin, as well as testosterone and cortisol, were sampled before and after dopamine receptor-2 (DRD2) antagonism with the drug Raclopride. Second, the behavior-pharmacological effects of agonizing or antagonizing DRD2 or dopamine receptor-1 (DRD1) were assessed by treatment with the drugs SKF81297, SCH23390, Quinpirole, and Raclopride. Third, relative densities of DRD1 and DRD2 in the prefrontal cortex and basal ganglia were quantified in postmortem brain specimens from similarly reared, juvenile, male rhesus monkeys (NR, n=6; MR, n=6). Compared to MR, NR monkeys exhibited lower dopaminergic tone, altered sensitivities to the pharmacological manipulation of DRD1 and DRD2, as well as reduced densities of orbitofrontal DRD1 and medial-prefrontal DRD2. Furthermore, some behavioral outcomes of nursery-rearing were associated with either low dopaminergic tone or altered levels of CSF dopamine metabolites. Consequently, brain dopamine systems are significantly influenced by early maternal deprivation and thus likely underpin the social and emotional deficits typically observed following early adversity in primates.
Supported by MH57704 (James T. Winslow), NSF STC Program (Agreement No. IBN-9876754), NARSAD (M. Mar Sanchez) and RR-00165.