Previous autoradiographic studies have demonstrated the location of alpha and beta adrenergic receptor binding with specific radioligands. In the present study, unique radiolabeled oligonucleotide probes were designed to sequences of the rat alpha(1B) brain alpha(2B), kidney alpha(2B), beta(1), and beta(2) adrenoreceptor mRNAs for use in in situ hybridization experiments on fresh rat tissues, including brain, spinal cord, and several peripheral organs. After sections were exposed to film or dipped in autoradiographic emulsion, specific and selective labeling patterns characteristic for each probe and tissue were observed. Examples of specific labeling include aIB in cerebral cortex, thalamus, dorsal and medullary raphe nuclei, liver, heart, and kidney; brain alpha(2B) in the hippocampal formation, spinal grey matter, parts of the basal ganglia, adrenal medulla, cerebral and cerebellar cortices, and sympathetic and dorsal root ganglia; beta(1) in cerebral cortex and heart; and beta(2) in hippocampus, trachea, and lung. The kidney alpha(2B) probe labeled kidney but not brain. Thus, using this technique, the locations of cells that produce the mRNA for these receptors were compared as a basis for future studies on the regulation of these mRNAs after physiological or pharmacological manipulations.