It is generally agreed that cortical processing of nociceptive stimuli is responsible for the more complex, non-reflexive, and clinically relevant aspects of pain. Human imaging studies are demonstrating the importance of specific cortical areas in nociception, the insular cortex in particular. Presently the neural circuits through which the cortex is involved in nociceptive processing remain largely unknown. We have previous identified a region within the insular cortex of the rat, the rostral agranular insular cortex (RAIC), which is involved in modulation of pain behavior. This proposal examines the neural mechanisms involved in RAIC mediated antinociception. Our most recent work has demonstrated that blocking dopamine reuptake in the RAIC, which receives dense dopaminergic innervation, produces sustained behavioral antinociception and inhibition of cell activity in nociceptive areas of the spinal cord. As a continuation of these studies, the aims of the present proposal are designed to test the following specific hypotheses: (1) that decreasing dopamine inhibition in the RAIC increases cellular activity in nociceptive areas of the brain; (2) that dopamine mediated antinociception in the RAIC involves GABAergic neurotransmission; (3) that thalamic afferents directly control the release of dopamine in the RAIC; and finally, (4) that dopamine is responsible for the antinociceptive effect of catecholamines in the RAIC independently of noradrenergic transmission. The present proposal will identify neural circuits involved in dopamine antinociception from the RAIC. While the role of dopamine in the forebrain has been the subject of extensive research in relatio9n to mood disorders and degenerative diseases, the present proposal is the first to examine the involvement of cortical dopaminergic neurotransmission in nociception. The clinical implications of loss of dopaminergic inhibition of the cerebral cortex include central pain syndromes such as those reported in Parkinson's disease and in patients treated with neuroleptic drugs.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS039320-03
Application #
6330607
Study Section
Special Emphasis Panel (ZRG1-IFCN-4 (01))
Program Officer
Kitt, Cheryl A
Project Start
1999-12-10
Project End
2002-11-30
Budget Start
2000-12-01
Budget End
2001-11-30
Support Year
3
Fiscal Year
2001
Total Cost
$123,476
Indirect Cost
Name
University of California San Francisco
Department
Neurosurgery
Type
Schools of Medicine
DUNS #
073133571
City
San Francisco
State
CA
Country
United States
Zip Code
94143
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Jasmin, Luc; Burkey, Adam R; Granato, Alberto et al. (2004) Rostral agranular insular cortex and pain areas of the central nervous system: a tract-tracing study in the rat. J Comp Neurol 468:425-40
Jasmin, Luc; Boudah, Abdennacer; Ohara, Peter T (2003) Long-term effects of decreased noradrenergic central nervous system innervation on pain behavior and opioid antinociception. J Comp Neurol 460:38-55
Ohara, Peter T; Granato, Alberto; Moallem, Theodore M et al. (2003) Dopaminergic input to GABAergic neurons in the rostral agranular insular cortex of the rat. J Neurocytol 32:131-41