[Ultrastructural in situ hybridization: detection of mRNA on sections of tissue embedded in lowicryl resin].

In situ hybridization for the detection of RNAm in ultrathin tissue sections embedded in lowicryl resin is reported. This method proved suitable for both tissues and cell cultures, using either complementary DNA probes or synthetic oligonucleotides, labeled with a radioisotope or biotin. This method seems to strike a satisfactory balance between preservation of cell ultrastructure and sensitivity.