Direct visualization of cholecystokinin subtype2 receptors in rat central nervous system using anti-peptide antibodies

The cholecystokinin receptor, subtype 2 (CCK2R), is considered, based on re ceptor autoradiography, to be the predominant receptor for this peptide tra nsmitter in the mammalian central nervous system. To directly visualize the CCK2R we utilized a convenient and sensitive immunohistochemical procedure using antipeptide receptor antibodies raised in rabbits against unique por tions of the carboxyl tail and third intracellular loop of the CCK2R. Antib odies were characterized by ELISA and Western blotting, and used for immuno histochemistry in rat brain sections. Studies with both antibodies revealed a widespread topographic distribution of CCK2R-like immunoreactivity (CCK2 R-LI) in regions such as cortex, olfactory bulb, nucleus accumbens, septum, striatum, hippocampus, basolateral amygdala, habenula, hypothalamus, thala mus, ventral mesencephalon, inferior colliculus, parabrachial nucleus, pont ine nucleus, supercolliculus, red nucleus, subcommisural and occulomotor nu cleus, area postrema, solitary, olivary, cochlear, cuneate and trigeminal n uclei and spinal cord dorsal horn in agreement with the results of previous receptor autoradiography. (C) 2000 Elsevier Science Ireland Ltd. All right s reserved.