Recent work has demonstrated that very low doses (1 mug/kg, i.v.) can approximately double the excitatory effect of NMDA iontophoretically applied to hippocampal (CA3) pyramidal neurons. Furthermore, the NMDA antagonist CPP was found to inhibit the increased glucose utilization produced by the sigma ligand DTG (1 mg/kg, i.p.), and CPP blocks the ability of DTG to cause increased dopamine release. Based on these findings it appears that sigma ligands (at least in some cases) positively modulate NMDA responses. Three sets of experiments are proposed to further examine this possibility in order to 1) Further characterize the interactions between sigma and NMDA in the hippocampus; 2) use the radioligand binding techniques to examine whether such interactions can be observed at the level of membrane-receptor interactions; and 3) to determine the generality of these interactions - i.e., to examine whether sigma/NMDA interactions are found in neural systems outside the hippocampus, with special emphasis on the nigrostriatal dopamine system. These experiments are relevant to mental health. Some experiments suggest that sigma ligands may serve as antipsychotic drugs, or as pharmacotherapeutic agents for antipsychotic drug-induced movement disorders. In addition, the investigations in the hippocampus may have relevance to learning and memory and thus have implications for certain mental illnesses such as Alzheimer's disease or other diseases that affect mental health.

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Scientist Development Award - Research (K02)
Project #
5K02MH001083-03
Application #
2240466
Study Section
Neuropharmacology and Neurochemistry Review Committee (NPNC)
Project Start
1993-06-01
Project End
1998-05-31
Budget Start
1995-06-01
Budget End
1996-05-31
Support Year
3
Fiscal Year
1995
Total Cost
Indirect Cost
Name
Brown University
Department
Psychology
Type
Schools of Arts and Sciences
DUNS #
001785542
City
Providence
State
RI
Country
United States
Zip Code
02912
Strangman, N M; Walker, J M (1999) Cannabinoid WIN 55,212-2 inhibits the activity-dependent facilitation of spinal nociceptive responses. J Neurophysiol 82:472-7
Sanudo-Pena, M C; Force, M; Tsou, K et al. (1999) Dopaminergic system does not play a major role in the precipitated cannabinoid withdrawal syndrome. Zhongguo Yao Li Xue Bao 20:1121-4
Sanudo-Pena, M C; Strangman, N M; Mackie, K et al. (1999) CB1 receptor localization in rat spinal cord and roots, dorsal root ganglion, and peripheral nerve. Zhongguo Yao Li Xue Bao 20:1115-20
Martin, W J; Tsou, K; Walker, J M (1998) Cannabinoid receptor-mediated inhibition of the rat tail-flick reflex after microinjection into the rostral ventromedial medulla. Neurosci Lett 242:33-6
Sanudo-Pena, M C; Patrick, S L; Khen, S et al. (1998) Cannabinoid effects in basal ganglia in a rat model of Parkinson's disease. Neurosci Lett 248:171-4
Sanudo-Pena, M C; Walker, J M (1998) A novel neurotransmitter system involved in the control of motor behavior by the basal ganglia. Ann N Y Acad Sci 860:475-9
Strangman, N M; Patrick, S L; Hohmann, A G et al. (1998) Evidence for a role of endogenous cannabinoids in the modulation of acute and tonic pain sensitivity. Brain Res 813:323-8
Hohmann, A G; Tsou, K; Walker, J M (1998) Cannabinoid modulation of wide dynamic range neurons in the lumbar dorsal horn of the rat by spinally administered WIN55,212-2. Neurosci Lett 257:119-22
Tsou, K; Nogueron, M I; Muthian, S et al. (1998) Fatty acid amide hydrolase is located preferentially in large neurons in the rat central nervous system as revealed by immunohistochemistry. Neurosci Lett 254:137-40
Sanudo-Pena, M C; Walker, J M (1998) Effects of intrapallidal cannabinoids on rotational behavior in rats: interactions with the dopaminergic system. Synapse 28:27-32

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