European Journal of Biomedical and Pharmaceutical Sciences

EFFECT OF MARIJUANA ON THE CENTRAL NERVOUS SYSTEM

*Debela Gemeda Bedane and Zewdu Jima Takle

ABSTRACT

Marijuana is the dried buds and leaves of the Cannabis sativa plant also known as hemp. Marijuana plants contain more than 400 chemicals, 60 of which fit into a category called cannabinoids. Delta-9-tetrahydrocannabinol (THC) is the primary psychoactive component of the plant. There are CB1, CB2 and GPR55 cannabinoid receptors. All are members of the super family of G protein-coupled receptors (GPCRs); both CB1and CB2 are coupled to Gi/o proteins but GPR55 couples to Gα11–13.CB1 are widely concentrate in specific brain areas that govern pleasure, movement, learning and memory and pain, which includes amygdale, basal ganglia, brain stem, cerebellum, hippocampus, hypothalamus, neocortex, nucleus accumbens, spinal cord. The effect on dopamine release most likely explains why Δ9-THC can induce signs of reward in animals. As THC enters the brain, it causes the user to feel euphoric or high by acting on the brain's reward system, which is made up of regions that govern the response to pleasurable things. A few users experience dysphoria, anxiety, even frank paranoia symptoms. The cannabinoids have also been shown to impact different stages of memory including encoding, consolidation and retrieval. Cannabis use has been implicated as a potential cause, aggravator, or masker of major psychiatric symptoms, including psychotic, depressive, mood and anxiety disorders. Chronic exposure to Δ9-THC and other cannabinoid receptor agonists generally leads to biological adaptive mechanisms that may be related to the phenomenon of tolerance and also withdrawal symptoms which include restlessness, irritability, mild agitation, insomnia, nausea, sleep disturbance, sweats and intense dreams. From a medical point of view, marijuana is a valuable drug. It lowers certain types of pain; has anti-anxiety, anti-inflammatory and anti-spastic effects; and enhances appetite. It also blocks vomiting.

Keywords: Marijuana; Cannabinoids; Cannabinoid receptors (CB); Delta-9-tetrahydrocannabinol (THC); Dopamine; Reward System.