ABSTRACT
This chapter focuses on the visualization and measurement of brain benzodiazepine receptors under various behavioral and pharmacological conditions using in vivo autoradiography and positron emission tomography (PET). The application of reliable in vivo autoradiography for benzodiazepine receptor distributions via PET will result in a better understanding of the neurobiology of anxiety and related disease states since this process will permit the visualization of site-specific changes in these receptors in the living human brain. Benzodiazepines are only the last in a series of compounds used as anxiolytics. Ethanol has been used and abused by individuals throughout recorded history in an attempt to "self-medicate" painful feelings associated with stress and anxiety. Benzodiazepines increase the behavior previously inhibited by the electric shock without affecting nonpunished responding. Benzodiazepines do produce sedation, and, therefore, they are the most frequently prescribed drugs used to treat insomnia. Benzodiazepines also decrease normal and, more importantly, pathologically elevated skeletal muscle tone.
