Somatostatin and analogs inhibit endogenous synaptic plasma membrane protein phosphorylation in vitro.
The addition of somatostatin to hippocampal synaptic plasma membrane (SPM) preparations in vitro decreased subsequent phosphorylation of specific protein bands. 10(-4)M somatostatin inhibited the phosphorylation of protein bands with apparent molecular weights between 10 000 and 20 000 daltons and, to a lesser extent, 48 000 daltons (B-50) and 52 000. Increasingly greater degrees of inhibition were seen in response to somatostatin-28 and [D-Trp8]somatostatin. Inhibition of B-50 protein phosphorylation in the presence of [D-Trp8]somatostatin was most prominent in SPM preparations from the hippocampus and amygdala, with lesser degrees of inhibition seen in the cortex and hypothalamus. Addition of [D-Trp8]somatostatin to an ammonium sulfate-precipitated fraction (ASP 55-80) from cortex only slightly inhibited endogenous B-50 phosphorylation. The injection of [D-Trp8] somatostatin intracerebroventricularly into rats did not induce excessive grooming behavior but resulted in barrel rotation. These results suggest that somatostatin and congeners affect SPM protein phosphorylation in a manner different from that of ACTH, presumably involving membrane sites that bind somatostatin.
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology; D000645:Ammonium Sulfate; D000818:Animals; D006120:Grooming / Q000187:drug effects; D006624:Hippocampus / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism*; D010766:Phosphorylation; D051381:Rats; D011919:Rats, Inbred Strains; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000494:pharmacology*; D013570:Synaptic Membranes / Q000187:drug effects* / Q000378:metabolism
D008565:Membrane Proteins; D013004:Somatostatin; D000324:Adrenocorticotropic Hormone; D000645:Ammonium Sulfate