Thalamic reticular nucleus parcellation delineated by VIP and TRH gene expression in the rat

The distribution of the mRNAs encoding VIP (vasoactive intestinal peptide) and TRH (thyrotropin releasing hormone) was examined in the thalamic reticu lar nucleus of the adult rat using hybridization histochemistry with S35-la beled oligoprobes. Low levels of TRH expression were found in a medial tier . High levels of VIP expression were found in neurons located in a lateral shell of the same portion. High levels of TRH expression were found in a ti er located dorsally and in a tier located ventrally to the first one. In th ese regions no VIP expression could be detected. These data suggest a parce llation of this nucleus according to thr differential expression patterns o f TRH and VIP. (C) 1999 Elsevier Science B.V. All rights reserved.