ACTH4--10 antagonism of morphine-induced behavioral activation in the mouse

The 4--10 fragment of adrenocorticotrophic hormone (ACTH4--10; Met-Glu-His-Phe-Arg-Trp-Gly) was administered intracerebroventricularly to C57Bl mice with and without concurrent systemic injection of a standard dose of morphine sulfate. Morphine produced stereotyped behavioral activation (running, environmental oblivion, Straub tail) which was antagonized in a dose related fashion by the ACTH fragment. This extends the range of opiate--ACTH4--10 interactions to a novel species and behavioral model, and is consistent with previous findings.