Postsynaptic receptors for cholecystokinin in the thalamic reticular nucleus: a possible modulatory system for sensory transmission

Abstract

Cholecystokinin (CCK) binding sites have been described in several areas of the brain with a particularly rich localization being found in the thalamic reticular nucleus (TRN). We have studied the distribution of CCK binding sites in the TRN using a high resolution autoradiographic technique and observed that the CCK receptors were dense throughout the whole nucleus. Using kainic acid excitotoxic lesions, it was demonstrated that CCK receptors were attached to postsynaptic elements and not to afferent fibers. These results are discussed in view of the known functional role of the thalamic reticular nucleus as an inhibitory control, gating all thalamic sensory transmission systems.