This an application for a NIDA RSDA award. The major focus of my research program is elucidating the cellular effects of cannabinoids (the principal psychoactive constituents of marijuana) in neurons with the aim of understanding the physiology underlying the behavioral actions of these compounds. Cannabinoids, acting at the neuronal cannabinoid receptor (CB-1), are potent modulators of ion channel function. Specifically, they inhibit N-and Q-type voltage-dependent Ca2+ currents and activate an inwardly-rectifying K+ current. These actions suggest that cannabinoids may elicit their behavioral effects by decreasing neuronal excitability and neurotransmitter release from CB-1-expressing neurons. Over the next five years we will extend our studies to the level of synaptic function emphasizing the following projects: l. Investigating if cannabinoids, and an endogenous cannabinoid, anandamide, inhibit neurotransmitter release in neuronal cultures and cell lines using imaging, RIA, and electrophysiological techniques. 2. Determining the G protein alpha subunits mediating cannabinoid receptor-effector coupling and the CB-1 domains important in this coupling. 3. Delineating the role of protein kinase C (PKC) in cannabinoid signaling. Recently we have found that ion channel modulation by cannabinoids is disrupted by PKC activation and that the CB-1 receptor is a PKC substrate. Future studies will determine if CB-1 phosphorylation occurs in situ and if neurotransmitter activation of PKC disrupts cannabinoid-mediated ion channel modulation. 4. Generating CB-l-specific antibodies for affinity purification, labelling and signaling experiments. The projects presented here range from those well within the PI's expertise to those beyond his current training. The rich, collaborative atmosphere at the University of Washington, and the PI's senior colleagues, makes the success of these projects likely. The proposed studies will significantly advance our understanding of the cellular actions of cannabinoids. There are three reasons why this is important: (1) Marijuana use is increasing and is a significant social issue, (2) cannabinoids have therapeutic potential and we need a firm appreciation of their cellular actions to exploit this potential; (3) we know little about the physiological role of endogenous cannabinoids in healthy or diseased brain. Funding of this proposal will permit the investigator sufficient research time to make substantial progress towards elucidating the neuronal basis for the behavioral effects of cannabinoids.

Agency
National Institute of Health (NIH)
Institute
National Institute on Drug Abuse (NIDA)
Type
Research Scientist Development Award - Research (K02)
Project #
5K02DA000286-02
Application #
2443386
Study Section
Special Emphasis Panel (SRCD (21))
Program Officer
Frankenheim, Jerry
Project Start
1996-07-01
Project End
2001-06-30
Budget Start
1997-07-01
Budget End
1998-06-30
Support Year
2
Fiscal Year
1997
Total Cost
Indirect Cost
Name
University of Washington
Department
Anesthesiology
Type
Schools of Medicine
DUNS #
135646524
City
Seattle
State
WA
Country
United States
Zip Code
98195
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Agarwal, Nitin; Pacher, Pal; Tegeder, Irmgard et al. (2007) Cannabinoids mediate analgesia largely via peripheral type 1 cannabinoid receptors in nociceptors. Nat Neurosci 10:870-9
Fu, Jin; Astarita, Giuseppe; Gaetani, Silvana et al. (2007) Food intake regulates oleoylethanolamide formation and degradation in the proximal small intestine. J Biol Chem 282:1518-28
Mackie, Ken (2007) From active ingredients to the discovery of the targets: the cannabinoid receptors. Chem Biodivers 4:1693-706
Katona, Istvan; Urban, Gabriella M; Wallace, Matthew et al. (2006) Molecular composition of the endocannabinoid system at glutamatergic synapses. J Neurosci 26:5628-37
Tam, Joseph; Ofek, Orr; Fride, Ester et al. (2006) Involvement of neuronal cannabinoid receptor CB1 in regulation of bone mass and bone remodeling. Mol Pharmacol 70:786-92
Straiker, Alex; Mackie, Ken (2006) Cannabinoids, electrophysiology, and retrograde messengers: challenges for the next 5 years. AAPS J 8:E272-6
Monory, Krisztina; Massa, Federico; Egertova, Michaela et al. (2006) The endocannabinoid system controls key epileptogenic circuits in the hippocampus. Neuron 51:455-66

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