Self-administration of drugs of abuse

It has been over 40 years since the technical aspects of automatic intravenous drug delivery to rodents were described. 1 The development of self-administration methodology provided a tremendous technological advance for investigating drug abuse and resulted in clear demonstrations that the behavioral actions of psychoactive substances could be investigated using the same methods used to evaluate the reinforcing effects of nondrug reinforcers. The intravenous route of administration has several methodological advantages over other routes. The drug is discretely presented through an intravenous catheter so that the concentration of drug delivered per unit time can be more accurately assessed. Further, there are no problems associated with drug spillage, the handling of animals, or other confounding variables such as taste.