History of Drug Exposure as a Determinant of Drug Self-Administration

The purpose of this paper is to review how a drug’s effectiveness in initiating and maintaining self-administration can be influenced by a subject’s past experience with drugs. Drug self-administration by humans and laboratory animals is considered an instance of operant behavior (), controlled by the subject’s genetic constitution, past history, and the current circumstances of drug availability (of Skinner, 1938). The influence of history of drug exposure on current drug-maintained behavior may be controlled, in turn, by the particular drugs and doses employed and the conditions under which the drug is administered. This discussion will focus on the ways in which a history of drug exposure can control later drug self-administration in laboratory animals. Effects of history of drug exposure on initiation of drug self-administration In order to study drug self-administration by laboratory animals, an experimenter must set up a situation in which subjects are exposed to some contingency between the occurrence of a specific response and delivery of a particular drug. For many drugs, no explicit behavioral or pharmacologioal history is necessary for the drug to maintain behavior. In one initial study, for example, Read more […]

Behavioral Pharmacology of Narcotic Antagonists

Narcotic antagonists are currently the major pharmacological alternative to methadone for the long-term treatment of narcotic addiction. The clinical utility of antagonist treatment is undergoing continuing evaluation (). Within the last five years, there have been several comprehensive reviews of research on narcotic antagonist drugs (). This review will focus upon some recent behavioral studies of narcotic antagonist drugs in man and in animals. It is now apparent that antagonist drugs may have a number of complex behavioral effects, in addition to antagonism of the pharmacological effects of opiate drugs (). Recent explorations of the aversive properties of some antagonists () have been complemented by studies of the positive reinforcing qualities of antagonist drugs. The finding that opiate dependent monkeys will work to produce an infusion of a narcotic antagonist under certain conditions () suggests the complexity of the process of drug-related reinforcement (). Narcotic agonists and antagonists each may maintain behavior that leads to their administration. Of the several compounds which have narcotic antagonist properties), only two appear to be relatively “pure” antagonists with minimal agonistic activity. Read more […]