Abstract

Groups of rats with chronically implanted electrodes in the septum, in the junctional nuclei between the anterior and posterior hypothalamus (anteromiddle), in the posterior hypothalamus and in the midbrain tegmentum were trained to self-stimulate. Rates of responding at various current intensities were measured. The effects of chiorpromazine, chiordiazepoxide, nortriptyline, imipramine and amphetamine on threshold and response rates were measured, and dose-response data were obtained. The sensitivity of the various sites in the brain to these drugs was determined by comparing the low-dose effect of the drugs for each site. These drugs caused both quantitative and qualitative changes in rates of responding at the four sites studied.