Identification of alpha 2-adrenoceptors in rat lymph nodes and spleen: an autoradiographic study

The anatomical localization and pharmacological characteristics of alpha 2-adrenoceptors were studied in rat lymphoid tissues by quantitative autoradiography with [3H]bromoxidine as a ligand. In lymph nodes, a significant density of these receptors was found in the capsule, interfollicular cortex and medullary cords, while only very low densities were observed in the paracortex and germinal centres. In the spleen, these receptors appeared to be mainly distributed in the marginal zone of white pulp as well as in the red pulp. These results suggest a role for alpha 2-adrenoceptors in the interaction between nervous and immune systems.