Prenatal Cocaine: Effects on Neonatal Rodent Vocalizations and Underlying Brain Regions (2011)

Undergraduates: George Jones, Elizabeth Cox

Faculty Advisor: Josephine Johns
Department: Biology

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In past studies, altered neonatal vocalizations have been a common fundamental difference observed in various animal models used for studying neurodevelopmental disorders. These studies suggest vocalizations can be used as an early predictive behavioral marker for infants at risk for detrimental outcome, however little information is known bridging altered neurobiology with altered vocalizations. This study measured vocalizations following prenatal cocaine exposure in Sprague Dawley rat pups at postnatal day (PND) 14 along with neuronal proliferation and maturation rates in three brain regions: Central Amygdala (CeA), Basolateral Amygdala (BLA), and the Dentate Gyrus (DG). Upon conception, pregnant female rats were divided into three different groups: chronic cocaine (receiving 15mg/kg B.I.D. s.c. between gestational days (GD) 1-20), chronic saline (1ml/kg B.I.D. s.c. between GDs 1-20), or untreated controls that were handled and weighed daily. On GDs 13-15 all pregnant rats received a morning injection of BrdU to label cells undergoing proliferation. On PND 14, one male and female pup was removed from the litter and vocalizations recorded by placement of pups on a cold scale. Following vocalization testing pups were immediately perfused, and brains were sliced at 50µm and stained with fluorescent immunohistochemistry for (BrdU), NeuN, and GFAP. Images of the CeA, BLA, and DG were acquired with a Leica confocal microscopy and are now being analyzed. Understanding the underlying altered neurobiology in specific brain regions associated with altered vocalizations has large potential for illuminating the intersection between physiology and behavior.