³H]-imipramine binding sites in fawn-hooded rats

The existence of high-affinity [³H]-imipramine recognition sites was demonstrated in membranes prepared from the cerebral cortex, hypothalamus and platelets obtained from fawn-hooded rats. The B_max and K_d values for [³H]-imipramine binding to cerebral cortical membranes were virtually identical to thos obtained with cortical membrane preparations of Sprague-Dawley rats. An NBR strain of rats, genetically related to fawn-hooded rats, was found to have significantly higher levels of [³H]-imipramine binding sites in cerebral cortical membranes when compared to fawn-hooded and Sprague-Dawley rats. All four strains of rats examined possessed extremely high densities of [³H]-imipramine binding sites in a purified platelet membrane fraction. These results do not support the finding of others that the cerebral cortex and platelets of fawn-hooded rats are virtually devoid of [³H]-imipramine binding sites.