Behavioral and neurotrophic activity of ACTH-(7-16)NH2.

The behavioral and neurotrophic effects of ACTH-(7-16)NH2 were assessed in a number of tests in which other ACTH fragments are active. Subcutaneous injection of ACTH-(7-16)NH2 increased motor activity of group-housed rats tested under low light intensity and induced hypokinesia in rats subjected to the mild stress of a nonfunctional "hot" plate. In rats with 6-OHDA lesions in the nucleus accumbens daily subcutaneous treatment with ACTH-(7-16)NH2 during the first week following the lesions reversed the lesion-induced motor hypoactivity. The ED50's for the effects of ACTH-(7-16)NH2 on the environmentally induced changes in motor activity, the stress-induced hypokinesia and the impaired motor activity of 6-OHDA lesioned rats were approximately 8 micrograms/kg. 6.3 micrograms/kg and 0.45 micrograms/kg respectively. It is concluded that ACTH-(7-16)NH2 may mimic the effect of an ACTH-like peptide in the brain involved in brain processes triggered by changes in the environment and by brain damage.