raclopride and Learning-Disabilities

The aim of the study was to assess the contribution of central dopaminergic and glutamatergic systems to the age-dependent loss of motor functions in rats. Rats of three age groups were compared: young (3-5-month-old), middle-aged (20-21-month-old) and old (29-31-month-old). The obtained results showed an age-dependent decline in the electromyographic (EMG) resting and reflex activities in the gastrocnemius and tibialis anterior muscles, as well as in the T-maze performance. Although these disturbances were accompanied with significant age-dependent decreases in the binding to NMDA, AMPA and dopamine D2 receptors, and a decline in the number of nigral dopamine neurons, they were significantly correlated with the loss of the binding to NMDA receptors only. The reduction in T-maze performance with aging was additionally correlated with a decrease in motor functions (EMG activity). The study suggests a crucial role of the loss of NMDA receptors in age-dependent motor disabilities, as well as in disturbances measured in the T-maze.

Topics: Aging; alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; Animals; Ankle Joint; Biomarkers; Biomechanical Phenomena; Brain Mapping; Cell Count; Dizocilpine Maleate; Dopamine; Electromyography; Female; Glutamic Acid; Learning Disabilities; Maze Learning; Movement Disorders; Muscle, Skeletal; Nerve Tissue Proteins; Pliability; Psychomotor Performance; Raclopride; Rats; Rats, Wistar; Reaction Time; Receptors, AMPA; Receptors, Dopamine D2; Receptors, N-Methyl-D-Aspartate; Substantia Nigra; Tyrosine 3-Monooxygenase