Cortistatin radioligand binding in wild-type and somatostatin receptor-deficient mouse brain.
Cortistatin-14 (CST-14) is a recently discovered member of the somatostatin family of neuropeptides. It shares 11 of its 14 amino acids with somatostatin-14 (SRIF-14). In the present study, binding sites for cortistatin-14 in the mouse brain were examined and compared to those for somatostatin using iodinated cortistatin-14 and iodinated somatostatin-14. By in vitro receptor autoradiography, high densities of cortistatin-14 and somatostatin-14 specific binding sites were detected in the cortex, hippocampal formation, basolateral amygdala and medial habenula. Unlabeled 100 nM cortistatin-14 inhibited iodinated somatostatin-14 binding in the hippocampus, but not in the cortex or amygdaloid nuclei. In somatostatin receptor subtype-2 knock-out (KO) mice, autoradiographic iodinated somatostatin-14 binding was observed in the hippocampus and habenula but was removed in the cortex and amygdaloid nuclei, specific iodinated cortistatin-14 binding sites were found in the hippocampus, habenula and throughout the cortex. We conclude that the somatostatin receptor subtype-2 is responsible for somatostatin binding in cortical and amygdaloid regions and that cortistatin predominantly interacts with the same receptors as somatostatin.
Spier
Avron D
AD
Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Fabre
Véronique
V
de Lecea
Luis
L
D000818:Animals; D001345:Autoradiography; D001667:Binding, Competitive; D001921:Brain / Q000166:cytology / Q000378:metabolism*; D007457:Iodine Radioisotopes; D008024:Ligands; D051379:Mice; D018345:Mice, Knockout; D009479:Neuropeptides / Q000378:metabolism*; D010456:Peptides, Cyclic / Q000378:metabolism*; D011869:Radioligand Assay; D017481:Receptors, Somatostatin / Q000172:deficiency* / Q000235:genetics / Q000378:metabolism*; D013004:Somatostatin / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
D007457:Iodine Radioisotopes; D008024:Ligands; D009479:Neuropeptides; D010456:Peptides, Cyclic; D017481:Receptors, Somatostatin; C467796:cortistatin 14; D014443:Tyrosine; D013004:Somatostatin; C093733:somatostatin receptor 2