Reinforcement marijuana

Chait LD and Zacny JP (1992). Reinforcing and subjective effects of oral D9-THC and smoked marijuana in humans. Psychopharmacology, 107, 255-262. 

These smoked substances interact with the brain s own cannabinoid receptors to trigger dopamine release from the mesolimbic reward system. There are two known cannabinoid receptors, CB1 (in the brain, which is coupled via G proteins and modulates adenylate cyclase and ion channels) and CB2 (in the immune system). The CB1 receptors may mediate not only marijuana s reinforcing properties, but also those of alcohol. There is also an endogenous cannabinoid system (the brain s own marijuana) capable of activating these cannabinoid receptors functionally. These ert-docannabinoids are synthesized by neurons and inactivated by reuptake systems and enzymes in both neurons and glia. 

A young marijuana smoker who hears a scientist or physician refer to these findings as the basic nature of marijuana intoxication will simply sneer and have his antiscientific attitude further reinforced, it is clear to him that the scientist has no real understanding of what marijuana intoxication is all about (see 105 for a comprehensive description of this d-ASC). 

Smoking marijuana is a very fast and direct way for THC to reach the bloodstream and the brain. The marijuana high can be felt in as little as 15 minutes. Because the pleasure felt by the marijuana user can be recreated easily and quickly, it is a very reinforceable experience. 

Achieving pleasant or euphoric moods is clearly a perceived benefit of marijuana use. But it is equally important to recognize that avoiding unpleasant moods or situations can be another important motivator and therefore provides another dimension of reinforcement. Both experiences—pleasure or avoidance of pain or sadness—can lead the teen marijuana user to become psychologically dependent on marijuana. In fact, researchers believe that teens who use marijuana to seek relief from emotional pains such as anger, depression, and family/school problems experience even stronger reinforcement for repeated marijuana use than those motivated by a desire for euphoria. Since daily users often seem to use... 

Marijuana (A9-tetrahydrocannibinol, THC) is unusual among drugs of abuse in that there is little evidence that it serves as a reinforcer in animal models of self-administration. It has also been difficult to demonstrate physical dependence. 

A young marijuana smoker who hears a scientist or physician refer to these findings as the basic nature of marijuana intoxication will simply sneer and have his antiscientific attitude further reinforced. 

Alcohol, like all addictive drugs, increases the brain s production of dopamine, which sends a strong reinforcing signal of pleasure and reward. Peter Thanos and colleagues from BNL reported that alcohol stimulates the pleasurable effects of marijuana (Behav. Brain Res., September 2,2005). 

Thanos administered drugs to block the brain s cannabinoid receptors, known as CBl. These brain receptors are directly involved in triggering the reinforcing properties of marijuana, and are believed to play a role in stimulating reward pathways in response to alcohol. 

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