High impact information on Sstr3

• Here we report on the molecular and functional characterization of a somatostatin-28 receptor (SSR-28) cloned from a rat brain cDNA library [1].
• Binding assays using radiolabeled somatostatin-14 and membranes from COS cells transfected with the cloned cDNA show that this receptor, SSR-28, has a higher binding affinity for somatostatin-28 (IC50 = 0.24 nM) than for somatostatin-14 (IC50 = 0.89 nM) [1].
• In situ hybridization indicates that SSR-28 mRNA is present in the granular and Purkinje cell layers of the cerebellum and in the large cells of the hypoglossal nucleus of the brain stem [1].
• Using specific anti-peptide antisera, we observed somatostatin receptor 3-like immunoreactivity in many brain regions, including the cerebral cortex, hippocampus, hypothalamus, amygdala and cerebellum [2].
• Electron microscopic analysis revealed that somatostatin receptor 3-like immunoreactivity is localized to the plasma membrane of neuronal cilia which extended into an intercellular pocket and showed a 9+0 filament pattern in their basal body and proximal segments [2].

Anatomical context of Sstr3

• Somatostatin receptor 3 mRNA was very abundant in the cerebellum and pituitary (in contrast to somatostatin receptor 1), but it was also found in hippocampus, amygdala, hypothalamus and in motor nuclei of the brainstem [3].
• In all of these regions (except for the cerebellar cortex), somatostatin receptor 3-like immunoreactivity was selectively targeted to 4-8-microm-long rod-shaped profiles which did not co-localize with axonal or dendritic markers [2].
• Expression of somatostatin receptor 3 mRNA in the motorneurones of the rat spinal cord, and the sensory neurones of the spinal ganglia [4].
• Here, we report the distribution of somatostatin receptor 3 (SSTR3) mRNA in spinal cord and spinal ganglia by in situ hybridization [4].

Other interactions of Sstr3

• Thus, somatostatin receptor 3 demonstrates a unique example of a G-protein-coupled receptor not localized to "classical" pre- or postsynaptic sites, but selectively targeted to neuronal cilia [2].

References