Age, strain, and semi-chronic hydergine treatment effects on motor activity and neuronal nucleic acid-protein metabolism in male mice

This study was designed to examine the effects of Hydergine (DHET), co-dergocrine mesylate, treatment on motor activity and neuronal nucleoprotein metabolism in several motor areas of the aging rodent brain, specifically the caudate-putamen (CP), the substantia nigra (SN), and the cerebral cortex layer V (CX). Three age groups of two different strains of mice were used which represented two different aging rates: DBA/2 male mice (short lived) and C57BL/6 male mice (long lived). A representative sample of each age group was injected (IP) daily with a single dose of either DHET (1 mg/kg) or vehicle (0.9% saline) solution for one month. Total spontaneous motor activity was measured using a File apparatus to assess the functional ability of the selected brain areas. Histochemical parameters measured included the relative RNA and protein contents from a homogeneous population of neurons within each nuclei. The RNA and protein contents were assessed with a scanning microdensitometer using azure B and Coomassie staining protocols, respectively. The results of this study provide evidence that DHET does have significant effects on neuronal functioning in the motor compartments studied at the behavioral as well as the histochemical level for DBA/2 male mice. The C57BL/6 strain showed parallel, but less significant, changes in the histochemical parameters and no statistical differences in motor activity. In addition, DHET treatment produced no sign of neurotoxicity within any of the brain nuclei in either strain.