A fundamental challenge for the neuroscience of drug addiction is to understand why some individuals undergo a transition from casual and recreational drug use to the compulsive patterns of drug seeking and drug-taking behavior, as well as the propensity to relapse, that are the hallmarks of addiction. Hence, the major goals of our group are: (1) to identify the persistent neurochemical changes that repeatedly administered drugs of abuse produce in the neural circuits that mediate reward and craving to cause addiction, (2) to characterize the genetic and environmental factors that determine individual differences in the ability of the drugs to produce these changes, and, (3) to establish whether these neuroadaptations indeed contribute to addictive behavior itself. For the last several years, we have investigated such mechanisms in animal models of behavioral plasticity (i.e., psychostimulant sensitization, drug self-administration paradigms) using a variety of biochemical methods (HPLC and brain microdialysis, radioligand binding, enzyme assays, and analysis of gene expression). A key feature of these studies is the use of a genetic animal model of sensation/drug seeking behavior, the Roman high-avoidance (RHA) rats, which are selectively bred for rapid acquisition of avoidant behavior in the shuttle-box. Our findings may contribute to the development of more effective treatments for addiction.

Osvaldo Giorgi, MD is a Professor of Pharmacology at the University of Cagliari School of Pharmacy at Cagliari, Italy. Dr. Giorgi received his M.D. degree at the University of Buenos Aires School of Medicine. He completed his training in biochemical neuropharmacology and psychopharmacology as a postdoctoral fellow of the National Research Council of Argentina (CONICET) and as a Fogarty Fellow at the Laboratory of Preclinical Pharmacology, NIMH, NIH (Washington, DC).

O. Giorgi, D. Lecca, G. Piras, P. Driscoll, M.G. Corda. Dissociation between mesocortical dopamine release and fear-related behaviours in two psychogenetically selected lines of rats that differ in coping strategies to aversive conditions. Eur. J. Neurosci. 17: 2716-2726, 2003.
O. Giorgi, G. Piras, D. Lecca, S. Hansson, P. Driscoll, M.G. Corda. Differential neurochemical properties of central serotonergic transmission in Roman high- and low-avoidance rats. J Neurochem. 86: 422-431, 2003.
G. Piras, D. Lecca, M.G. Corda, O. Giorgi. Repeated morphine injections induce behavioural sensitization in Roman high-, but not in Roman low-avoidance rats. Neuroreport 14: 2483-2488, 2003.
D. Lecca, G. Piras, P. Driscoll, O. Giorgi, M.G. Corda. A differential activation of dopamine output in the shell and core of the nucleus accumbens is associated with the motor responses to addictive drugs: A brain dialysis study in Roman high- and low-avoidance rats. Neuropharmacology 46: 688-699, 2004.
M.G. Corda, G. Piras, D. Lecca, A. Fernández-Teruel, P. Driscoll, O. Giorgi. The psychogenetically selected Roman rat lines differ in the susceptibility to develop amphetamine sensitization. Behav. Brain Res. 157: 147-156, 2005.
O. Giorgi, G. Piras, D. Lecca, M.G. Corda. Behavioural effects of acute and repeated cocaine treatments: A comparative study in sensitisation-prone RHA rats and their sensitisation-resistant RLA counterparts. Psychopharmacology, 180: 530-538, 2005.
O. Giorgi, D. Lecca G. Piras, M.G. Corda. Differential activation of dopamine release in the nucleus accumbens core and shell after acute or repeated amphetamine injections: A comparative study in the Roman high- and low-avoidance rat lines. Neuroscience, 135: 987-998, 2005.
M.G. Corda, G. Piras, O. Giorgi. Neonatal ventral hippocampal lesions potentiate amphetamine-induced increments in dopamine efflux in the core, but not shell, of the nucleus accumbens. Biol. Psychiatry 60: 1188-1195, 2006.
O. Giorgi, G. Piras, M.G. Corda. The psychogenetically selected Roman high- and low-avoidance rat lines: A model to study the individual vulnerability to drug addiction. Neurosci Biobehav Rev., 31: 148-163, 2007.