Rationale: Among the various experimental protocols that have been used to measure drug
reward in laboratory animals, conditioned place preference (CPP) has been one of the most …

Drug addiction is a chronic relapsing brain disorder characterized by neurobiological
changes that lead to a compulsion to take a drug with loss of control over drug intake. The …

The transition from stable to escalated levels of cocaine self-administration has been shown
to depend upon drug availability. The generality of this phenomenon is assessed here by …

Self-administration of addictive drugs in laboratory animals has been widely used for
decades as a tool for studying behavioral, neurobiological, and genetic factors in addiction …

The activation of dopamine (DA) neurotransmission plays a crucial role in the behavioural
responses to drugs of abuse. In particular, increased extracellular levels of DA within the …

Opiate reinforcement has been hypothesized to be mediated by an inhibition of mesolimbic
γ-aminobutyric acid (GABA) release that subsequently disinhibits ventral tegmental area …

Nicotine is almost universally believed to be the major factor that motivates smoking and
impedes cessation. Authorities such as the Surgeon General of the USA and the Royal …

Rationale: Second-order schedules of heroin self-administration provide a method of
measuring heroin-seeking behaviour independently of the effects of the drug on motor …

Rationale: The involvement of nucleus accumbens (NAc) in initiating opiate-induced reward
has been difficult to demonstrate in rats, and has not been studied in mice. Objectives: To …

Preclinical and clinical studies suggest that the mesolimbic dopamine system plays a major
role in mediating the reinforcing effects of drugs of abuse, including alcohol and …