California Cannabis Research Medical Group


O'Shaughnessy's Home

This Issue Home







Autumn 2005
Journal of the California Cannabis Research Medical Group

Addiction and Learning

Gregory Gerdeman’s poster described how behavior in rats associated with drug dependence — “amped-up running around the cage” after an injection of cocaine— diminished dramatically after five days on Rimonabant.

“ I’m funded to look at mechanisms of drug reward and addiction,” says Gerdeman. “I’m interested in how the cannabinoids interact with that. The pathways of drug reward interact with the pathways of motor function and are key to understanding psychomotor disorders like Parkinsons and, I believe, obsessive-compulsive disorder and Tourette’s syndrome.”

Gerdeman studies an area of the brain called the nucleus accumbens. His experiments question: By what mechanisms do neurons change their synaptic connection as habits are learned and unlearned? How, exactly is the endocannabinoid system involved? By what mechanism does the antagonist compound (Rimonabant) disrupt learning and memory at the cellular level?

Gerdeman, 31, is a naturalist, as interested in ocean life as he is in neurotransmission. He has a knack for clear exposition. With his long hair, soft spoken manner and democratic commitment to keeping the public (your correspondent) informed about advances in his field, I imagined that he might feel constrained, if not compromised, by reliance on funding from NIDA. I asked directly, “Did you do this work because of your interest in addiction or because you knew NIDA was interested in addiction? Did the fact that the money is there for this kind of research influence your study design?”

Gerdeman replied, “My interest is synaptic plasticity, which refers to brain mechanisms of cellular learning. These processes are involved in drug addiction, which I see as a strongly learned state of thinking and behavior. The cellular pathways we relate to ‘learning’ addiction are sensitized by addictive drugs and are clearly modulated by cannabinoids. I joined a lab as a postdoc and our funding structure is from NIDA and it is a grant based on studying the connection between cannabinoids and drug-abuse paradigms. That’s what the experiments were proposed to do. So yes, focusing on addiction is where the funding is, and it’s a major part of keeping my agreements about where I spend the money.

I think the therapeutic role of Rimonabant is interesting but what compels me is using the drug as a tool to investigate the function of endocan-nabinoids. It’s interesting that Rimonabant may be effective to help curb a psychostimulant addiction, especially given the credible reports that some people use cannabis as a substitution therapy for addiction. That’s something that I’ve had in mind as I’ve been doing the NIDA-funded work.

“ If this neurocircuitry choreographed by endocannabinoids is playing a role in sustaining our habitual behavior, it is likely not a simple matter of the cannabinoid receptor being some kind of on-switch and when you turn it off you’re blocking addiction. It’s not anything so elementary like that. There are discrete neural circuits involved in our behaviors and how we define them to ourselves. When you start to influence that circuitry through manipulation of the cannabinoid system, it may open windows for rewiring the pathways related to your habitual behavior. Intention also feeds into this, and is very, very important. It’s been long known that people have to have a motivation to quit drugs.”

O'Shaughnessy's is the journal of the CCRMG/SCC. Our primary goals are the same as the stated goals of any reputable scientific publication: to bring out findings that are accurate, duplicable, and useful to the community at large. But in order to do this, we have to pursue parallel goals such as removing the impediments to clinical research created by Prohibition, and educating our colleagues, co-workers and patients as we educate ourselves about the medical uses of cannabis.
The Society of Cannabis Clinicians (SCC) was formed in the Autumn of 2004 by the member physicians of CCRMG to aid in the promulgation of voluntary standards for clinicians engaged in the recommendation and approval of cannabis under California law (HSC §11362.5).

As the collaborative effort continues to move closer to issueing guidelines, this site serves as a public venue for airing and discussing these guidelines.

Visit the SCC Site for more information.