Individual Differences in Amphetamine Locomotor Sensitization are Accompanied with Changes in Dopamine Release and Firing Pattern in the Dorsolateral Striatum of Rats.

Not all the people that consume drugs of abuse develop addiction. In this sense, just a percentage of rats express locomotor sensitization after repeated psychostimulant exposure. Neurochemical evidence has shown that locomotor sensitization is associated with changes in dorsolateral striatum (DLS) activity.

The blocking of kappa-opioid receptor reverses the changes in dorsolateral striatum dopamine dynamics during the amphetamine sensitization.

Kappa-opioid receptors (KOR) control dopamine (DA) levels in the striatum and contribute significantly to the progression of drug addiction. Repeated exposure to psychostimulants has been associated with up-regulated KOR activity and increased DA levels in dorsal striatum. However, it has not been tested if both processes are linked.