Pharmacologic determinants of tobacco self-administration by humans.

Tobacco is a naturally occurring source of nicotine, which is a chemical of demonstrable abuse liability and dependence potential. All commonly used forms of tobacco result in the delivery of nicotine to the central nervous system (CNS), where its actions affect the probability of subsequent use. The role of nicotine as a determinant of patterns of tobacco self-administration and other tobacco-associated responses has frequently been confounded by the complexity of this form of drug self-administration, since the amount of nicotine delivered to the CNS is not a simple function of the amount of tobacco consumed. The present paper is a summary of data which indicate that nicotine administration and withdrawal are determinants of tobacco ingestion. Recent data that are reviewed include those which indicate that the following effects of nicotine bear an orderly relation to the dose administered: (1) reduction of cigarette smoking, (2) production of discriminative effects, and (3) blockade of tobacco withdrawal symptoms. A secondary intent of the present paper is to describe aspects of tobacco dependence which are relevant to the appreciation of the subsequent papers appearing in this series of eight.