Localization of vasopressin mRNA in the rat brain using in situ hybridization with short cRNA probes made from synthetic DNA templates.

Short antisense and sense RNA sequences were transcribed from annealed double stranded oligodeoxynucleotide templates containing the T7 RNA polymerase promotor sequence and its complementary sequence, together with 5' overhanging sequence corresponding to either the sense or antisense sequences of part of the rat vasopressin gene to produce after transcription 35S-labelled sense or antisense RNA for use in situ hybridization histochemistry. Labelled antisense RNA coding for a vasopressin sequence visualized sites of vasopressin mRNA expression (as did the 35S-labelled antisense oligodeoxynucleotide sequence), whereas sense RNA sequences revealed no specific sites of hybridization. This method represents an accessible, convenient and general method for the generation of cRNA probes suitable for use in situ hybridization.