This study examined the effects of neonatal cocaine exposure on responsivity to the α2 noradrenergic agonist clonidine in 11-day-old rat pups. On postnatal day (PND) 4 neonatal rats were assigned to one of four treatment groups: artificially reared (AR) receiving 40 mg/kg/day cocaine hydrochloride, AR receiving 20 mg/kg cocaine, AR control receiving no drug, and a normally reared control group. Pups were maintained in this fashion from PND 4 to 9 and received no drug on PND 10. On PND 11 subjects received an IP injection of either 0, 0.25, or 1.0 mg/kg clonidine hydrochloride and were observed for locomotor activity and wall-climbing during a 15-min test session. Subjects exposed to the 40 mg/kg dose of cocaine demonstrated an enhanced sensitivity to the locomotor stimulating effects of clonidine relative to both control groups. This cocaine-related enhanced sensitivity was not observed on the wall-climbing measure. All groups showed evidence of wall-climbing, although this behavior was somewhat dampened among AR groups. The 20 mg/kg cocaine-exposed males also took longer to display wall-climbing behavior than their respective females regardless of clonidine dose, although this sex difference was not apparent for any other treatment group. These findings suggest that neonatal cocaine exposure may alter response of the noradrenergic system.
|Number of pages||9|
|Journal||Neurotoxicology and Teratology|
|State||Published - Jul 1998|
Bibliographical noteFunding Information:
This work was supported, in part, by NIDA DA06049 to S.B. and a Howard Hughes Undergraduate Research Award awarded to C.M.S. The authors would like to acknowledge Purina Protein International for supplying protein for the liquid diet and Clay Adams International for assistance with polyethylene tubing. The authors would also like to thank Todd Bonta and Bryan Baseheart for technical assistance with this project.
- Locomotor activity
- Neonatal cocaine exposure
ASJC Scopus subject areas
- Developmental Neuroscience
- Cellular and Molecular Neuroscience