Partial agonistic action of endomorphins in the mouse spinal cord

The partial agonistic properties of endogenous L-opioid peptides endomorphi n-1 and endomorphin-2 for G-protein activation were determined in the mouse spinal cord, monitoring the increases in guanosine-5'-o-(3-[S-35]thio)trip hosphate binding. The G-protein activation induced by endogenous opioid pep tide beta -endorphin in the spinal cord was significantly, but partially, a ttenuated by co-incubation with endomorphin-1 or endomorphin-2. The data in dicates that endomorphin-1 and endomorphin-2 are endogenous partial agonist s for mu -opioid receptor in the mouse spinal cord. (C) 2001 Published by E lsevier Science Ireland Ltd.