Localization of prodynorphin messenger RNA in rat brain by in situ hybridization using a synthetic oligonucleotide probe

An in situ hybridization technique has been developed to study the distribution of messenger RNA (mRNA) encoding prodynorphin (proenkephalin B) in sections of rat brain. A 100-mer oligonucleotide was used as a template to synthesize a 32P-labelled DNA probe complementary to the coding region of rat prodynorphin mRNA. Using this probe, dense labelling was observed in the supraoptic and paraventricular nuclei of the hypothalamus, in the striatum and in the dentate gyrus. The results show for the first time the localization of prodynorphin mRNA in rat brain, and additionally demonstrate the usefulness of oligonucleotides to detect rare mRNAs by in situ hybridization.