Cyclosomatostatin is a non-selective SSTR (somatostatin receptor) antagonist. Effects of SST are blocked on release of growth hormone, insulin and glucagon, airway β-adrenergic function, modulation of ACh release and CRF-induced suppression of gastric empyting. Cyclosomatostatin potentially acts as an SSTR agonist in human neuroblastoma cell line SH-SY5Y.