Motoric behavior in aged rats treated with GM1

Aging is associated with impaired motor function. Nigrostriatal dopaminergi c neurons, in part, regulate motoric behavior, and undergo degenerative cha nges during aging. GM1 ganglioside partially restores pre-synaptic dopamine rgic markers and the number and morphology of dopaminergic neurons in the m idbrain and striatum of Sprague-Dawley aged rats. These studies investigate d whether GM1 treatment. 30 mg/kg, i.p. daily for 36 days, affects locomoto r and stereotypic activity, as well as coordination, balance, and strength in aged rats. Under the treatment conditions used, GM1 did not improve the reduced locomotor and stereotypic behavior of the aged rats. While it parti ally improved performance on a square bridge test. GM1 had no effect on inc lined screen and rod suspension tests. Although GM1 restored the decreased content of dopamine and homovanillic acid in the nigrostriatal neurons of t he aged rats, it had no effect on the reduced D1 and D2 dopamine receptor b inding and mRNA in the striatum. It appears, that despite the morphological and metabolic restoration of aged nigrostriatal neurons, GM1 has limited a bility in improving age-associated motor deficits. (C) 2001 Elsevier Scienc e B.V. All rights reserved.