G. Kirouac
Professor

kirouac@cc.umanitoba.ca

Neurobiology of Addiction

The brain contains specialized regions that mediate the rewards and pleasures of everyday life. Unfortunately, the same regions of the brain are also activated by addictive drugs like cocaine, morphine, nicotine and alcohol, and may lead to uncontrollable use of these substances. In fact, the Canadian Community Health Survey (2002) estimated that 600,000 Canadians were dependent of alcohol and 200,000 on illicit drugs. Despite significant advances in the treatment of addicted individuals, nearly half of addicts eventually relapse to an uncontrolled use of the addictive substance. Stress and exposure to the environmental situations associated with previous drug taking have been identified as contributors to relapse to substance use.

Research in our laboratory has established that certain areas of the midline thalamus are strongly connected to parts of the brain associated with motivation and emotions. The paraventricular nucleus of the midline thalamus is of special interest because it is strongly activated by stressful and environmental situations associated with addictive drugs, two important factors in producing relapse in addicts. In addition, the paraventricular nucleus contains a high concentration of novel neuropeptides associated with drug addiction and stress (orexins, CART, neuropeptide S, CRF) and may provide novel pharmacological targets to treat addiction.

Consequently, we are interested in determining how neuropeptides act on the paraventricular nucleus to influences motivation, emotions, and addictive behaviors. We do this by using tract-tracing, immunohistochemistry, electrophysiology, and electrochemistry applied to animal models to study the anatomy and neurophysiology of the paraventricular nucleus. We hope that this research will provide preclinical data that may be useful for designing new therapeutic approaches for the treatment of addiction.

Relevant publications

• Li, S. and Kirouac, G.J (2008) Projections from the paraventricular nucleus of the thalamus to the forebrain with a special emphasis on the extended amygdala. J. Comp. Neurol., 506, 263-287.
• Parsons, M.P., Li, S. and Kirouac, G.J. (2007) Functional and anatomical connection between the paraventricular nucleus of the thalamus and dopamine fibers of the nucleus accumbens. J. Comp. Neurol., 500, 1050-1063.
• Kirouac, G.J., Parsons, M.P. and Li, S. (2006) Innervation of the paraventricular nucleus of the thalamus from cocaine- and amphetamine-regulated transcript (CART) containing neurons of the hypothalamus. J. Comp. Neurol., 497, 155-165.
• Parsons, M.P., Li, S. and Kirouac, G.J. (2006) The paraventricular nucleus of the thalamus as an interface between the orexin and CART peptides and the nucleus accumbens. Synapse, 59, 480-490.
• Kirouac, G.J., Parsons, M.P. and Li, S. (2005) Orexin (hypocretin) innervation of the paraventricular nucleus of the thalamus. Brain Res., 1059, 179-188.