Regulation Of Dopamine Receptors On Cocaine Induced Gene Expression And MAPK Signaling Pathway Activation

Drug addiction can be defined as the compulsive seeking and taking of drugs despite adverse consequences, and is a long lasting condition involving persistent neuroadaptation in the brain. Addiction is caused by the actions of a drug of abuse on a vulnerable brain and generally requires repeated drug exposure. This process is strongly influenced both by the genetic makeup of the person and by the psychological and social context in which drug use occurs. Once formed, an addiction can be a life-long condition in which individuals show intense drug craving and increased risk for relapse after years and even decades of abstinence. This means that addiction involves extremely stable changes in the brain that are responsible for these long-lived behavioural abnormalities.The brain dopamine (DA) system that originates from the midbrain and projects to the nucleus accumbens (NAc), caudoputamen (CPu), and other forebrain structures is a key neural substrate for mediating persistent changes induced by repeated exposure to abused drugs. The DA receptors identified so far can be grouped into two classes, the D1-class (D1 and D5) and the D2-class (D2, D3 and D4) receptors. The D1-class receptors couple to Gs G-proteins and activate adenylyl cyclases, while the D2-class receptors couple to Gi or GO G-proteins and inhibit adenylyl cyclases. The D1 receptor...