First localisation of somatostatin sst(4) receptor protein in selected human brain areas: an immunohistochemical study

Somatostatin is known to have diverse neurophysiological effects in the mam malian CNS. To date, genes for five different receptors, termed sst(1-5), h ave been isolated. Recently several reports have been published on the loca lisation of the individual receptor protein in the rat CNS, but their local isation in the human CNS remains largely unknown. Until now little informat ion about the function of the sst(4) receptor is available, and there is a lack of receptor specific agonists and antagonists. Here, we report for the first time the immunohistochemical localisation of the sst(4) receptor in selected human brain areas using an anti-peptide antibody raised against a carboxy-terminal portion of the receptor protein. Strong receptor immunorea ctivity was found in several brain regions, including the hippocampal forma tion, the cerebellar cortex and the medulla. Further immunohistochemical la belling was observed in the cerebral cortex, the red nucleus and the globus pallidus. Somatodendritic as well as axonal staining was observed. Specifi c signals were entirely absent following antibody pre-adsorption with the s ynthetic peptide. The results are in good agreement with the previously pub lished immunohistochemical localisation of the sst(4) receptor in the rat b rain. This is the first immunohistochemical study of the localisation of th e sst(4) receptor in the human brain, and implicates this receptor in the f unction of higher centres of the human nervous system. (C) 2000 Elsevier Sc ience B.V. All rights reserved.