ABSTRACT
This chapter provides a concise description of the most common methodologies employed to localize and characterize sites of drug action in the brain: quantitative in vitro autoradiography (QAR) and positron emission tomography. Autoradiography is a relatively old technique permitting qualitative localization of radioactivity in tissues through the use of radiation sensitive detectors such as emulsion or film. Quantitative autoradiography is a relatively recent development, made possible by several theoretical and technical advances; namely, the incorporation of standards, the invention of tritium sensitive film, and the availability of computerized image analysis systems. Generally, autoradiographic localization of drug binding sites in the human brain is attempted after the biochemical/pharmacological nature of the sites and optimal conditions for their labeling have been identified in animal and/or human brain homogenates.
