DIFFERENTIAL LOCALIZATION OF 3 DISTINCT BINDING-SITES FOR SIGMA-RECEPTOR LIGANDS IN RAT SPLEEN

In vitro receptor autoradiography was used to localize sigma(1) recept ors, sigma(2) receptors, and novel haloperidol/DTG-inaccessible sites for sigma and opiate ligands in rat spleen. Sigma-1 receptors were pre sent throughout the spleen, but were most concentrated in the T cell z ones. Binding under 'sigma(2) receptor-selective' conditions was 70% n onspecific, and sigma(2) receptors could not be detected. Haloperidol/ DTG-inaccessible sites had a course, punctate distribution in the red pulp and marginal zones of the white pulp. This anatomical localizatio n suggests types of cells and functions that should be examined for mo dulation by sigma receptors.