Immunohistochemical localization of the kappa1 opioid receptors

Abstract

Using antibodies generated to the C-terminal 41 amino acids of the cloned rat kappa receptor, the present study examines the distribution of the kappa1 receptor-like immunoreactivity (li) using immunohistochemical techniques. The localization of the kappa1 receptor staining generally corresponds well to previous receptor binding and in situ hybridization studies, with stained fibers and/or cells observed in such regions as the endopiriform nucleus, claustrum, nucleus accumbens, olfactory tubercle, bed nucleus stria terminalis, medial preoptic area, paraventricular, supraoptic and lateral hypothalamus, median eminence, thalamus, medial amygdala, parabrachial nucleus, nucleus of the solitary tract, and the superficial layers of the spinal cord. This localization is consistent with the wide range of functions associated with kappa1 receptors, including analgesia and hormonal regulation.