In medicine, A9- THC has been useful in treating symptoms caused by chemotherapy, and in treating the anorexia caused by the Acquired Immune Deficiency Syndrome. The CB1 receptor is mainly present in the brain. Marijuana effects depend on the activation of the CB1 and CB2 receptors, distributed in the entire body. Among the adverse effects marijuana causes alteration of short-term memory, slowness of reflexes, depression and anxiety, bronchitis and lung infections.

Marijuana causes euphoria followed by relaxation and several other reinforcing effects. It actually contains over 60 cannabinoids as well as other chemical compounds. Marijuana ( Cannabis sativa) is a plant which has its active principle A9- tetrahydrocannabinol ( THC) in almost all its parts, i. Only for marijuana it seems to be mild, misleading people to believe this drug does not cause physical dependence. Therefore when a long term user quits and deprives the brain abruptly of these drugs, an abstinence syndrome is precipitated and it may be quite severe. Such changes underlie the patient's dependence to drugs. The risk of dependence is related to the velocity with which these drugs induce plastic changes in the brain, very much like a learning process. All of them cause an effect on the brain, modifying the activity of the neuronal systems, altering the activity or availability of the neurotransmitters or emulating their actions. The drugs that are reviewed are marijuana, heroin, cocaine, methamphetamine and 3,4- methylenedioxymethamphetamine or MDMA, also known as ecstasy. We describe the effects, action sites and pathophysiological consequences of the use of these illicit drugs. In this second paper of the Brain, Drugs and Genes review we would like to discuss illicit drugs and the genetics that may predispose subjects to addiction.

Efectos del alcohol en el cerebro