Labratory Research

Self-Administration of Opiates
In order to examine the acute and long-term effects of drug exposure during various stages of postnatal development, we use the operant behavior model of intravenous drug self-administration in rats.  We are interested in differential drug effects between genders, so both males and females are tested in most of our experiments.  The overall goal is to explore the ontological development of reinforcement, as well as the social and physiological factors influencing drug use and effects in developing rats.  Drugs of interest in the opiate class include morphine and heroin.  Specific projects are described below.

1. Morphine Self-Administration in Periadolescent vs. Adult Rats:  Few studies analyze the effects of opiate drugs in operant behavioral paradigms across ontogeny.  In other studies of opiate drug-related behaviors, locomotor sensitization appears to differ between periadolescent and adult subjects, but morphine conditioned place preference does not.  We have brought the question into our laboratory by testing acquisition and maintenance of intravenous morphine self-administration in periadolescent and adult, male and female rats. 
   
   
2. Long-Term Impact of Neonatal Injury on Opiate Drug Self-Administration:  In collaboration with Dr. Anne Murphy of GSU’s Department of Biology, we are testing the long-term effects of neonatal injury (induced inflammatory response on postnatal day 0) on morphine self-administration in periadolescent and adult, male and female rats.  This behavioral assay will be accompanied by molecular and cellular analysis of opioid receptor expression and activity using G-protein activation studies, immunocytochemistry, and receptor binding assays.  Together these studies may identify the neural substrates involved in differential morphine-related behavior. 

J. Doherty presents a morphine self-administration poster at the South East Nerve Net meeting 2006