Marijuana is one of the most widely used illicit drugs in Canada and the United States. When smoked, marijuana typically results in a sense of mild euphoria and relaxation. The agent that is responsible for the majority of the psychoactive effects experienced after the use of marijuana is tetrahydrocannabinol (THC).
The mechanism of action of marijuana involves the binding of THC to specific receptors called cannabinoid receptors. When THC is released, it diffuses across the synaptic cleft and binds to cannabinoid receptors on the presynaptic neuron. This binding inhibits the release of excitatory neurons into the synaptic cleft; the overall effect is depression of the central nervous system. The mechanism of THC is unique in that it travels backwards to affect the presynaptic neuron; most neurotransmitters are released from the presynaptic neuron and bind to receptors located on the postsynaptic neuron. Three endogenous ligands are …show more content…
CB1 receptors were determined to be mainly localized to axons and nerve terminals, which is consistent with the theory that cannabinoid receptors are found on the presynaptic neuron (Iverson 2003). CB1 receptors are typically found in very high densities in the basal ganglia, the cerebellum, the frontal region of the cerebral cortex, the hypothalamus and the anterior cingulate cortex. The receptors are found to be relatively absent in the brainstem, which can explain why marijuana is relatively non-lethal as it does not depress respiration. CB1 receptors have been determined to be responsible for the majority of the psychoactive effects produced by marijuana (Scholten et al. 2006). CB2 receptors are found outside of the central nervous system. Typically, these receptors are thought to be responsible for the immunosuppressive properties of THC as it binds to the CB2 receptors on