Cell Biochemistry and Function 2008-12-01

Dynorphin inhibits NEP activity in R1.1 mouse thymoma cells.

Irena Martin-Kleiner, Tihomir Balog, Tanja Marotti

Index: Cell Biochem. Funct. 26(8) , 916-9, (2008)

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Abstract

NEP/CALLA or CD10 is an endopeptidase (E.C. 3.4.24.11) that inactivates numerous neuropeptides, including dynorphin. Dynorphin is an endogenous opioid polypeptide that binds to kappa-opioid receptors with greatest affinity. R1.1 mouse thymoma cells highly express kappa-opioid receptors. In this study, on R1.1 cells, NEP activity was inhibited by kappa-opioid polypeptide dynorphin (10(-8)-10(-6) M) and by thiorphan (2 x 10(-4) M), a known inhibitor of NEP (30 min treatment). NEP inhibition by dynorphin was stronger than by thiorphan. A non-opioid opioid mechanism of action was mostly involved in this inhibition.