In situ hybridization of putative somatostatin mRNA within hypothalamus of the rat using synthetic oligonucleotide probes

Abstract

The distribution of mRNA with high sequence homology to somatostatin mRNA within the periventricular hypothalamus of rat was assessed using in situ hybridization techniques with synthetic oligodeoxyribonucleotide probes, complementary to the 3′ coding region of rat somatostatin mRNA. The probes (22‐ and 24‐mers) were 5′‐end labeled using T4 polynucleotide kinase and γ‐³²P‐ATP. They were used either individually or after ligation with T4 DNA ligase to form a 46‐mer. Serial tissue sections ( < 10 μm) were taken from the level of the preoptic/anterior hypothalamus through the paraventricular hypothalamus. In situ hybridizations were conducted at room temperature in hybridization buffer. Neurons immuno‐reactive with antiserum raised against somatostatin were identified in alternate sections using standard immunocytochemical procedures. The anatomical location of the hybridization signal was determined by autoradiography. Our results show that the peri‐ and paraventricular hypothalamus is rich in transcripts putatively coding for somatostatin and that these transcripts are co‐distributed with neurons immunoreactive with antisomatostatin immunoglobulin.