Age-related changes in striatal function of freely-moving F344 rats.
Multi-wire electrode arrays were used to record extracellular electrophysiological activity in striatal medium spiny-like neurons of freely-moving young (6-8 months) and aged (24-26 months) Fischer 344 rats. While overall basal firing rates did not differ between the two groups, d-amphetamine (5.0 mg/kg) increased firing rates more in the young rats. D-Amphetamine had heterogeneous effects on firing rates, however, exciting 63% of the neurons while inhibiting 37%. Neurons were classified according to their response to d-amphetamine (excited vs. inhibited) to examine age-related differences in firing rates and bursting activity. In the d-amphetamine-excited neurons, pre-drug intraburst firing rates were higher in the old rats. This effect was reversed by d-amphetamine. D-Amphetamine increased the percentage of spikes within bursts to a greater extent in the aged animals and decreased burst durations greater in the young group. In d-amphetamine-inhibited neurons, firing rates were diminished in the old rats more than they were in the young rats. These results demonstrate age-related alterations in striatal electrophysiological activity that may help explain motor deficits seen in senescence.
Stanford
J A
JA
Department of Anatomy & Neurobiology, The University of Kentucky, Lexington, KY 40536-0098, USA. jastan2@pop.uky.edu
Gerhardt
G A
GA
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000375:Aging / Q000502:physiology*; D000818:Animals; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D003342:Corpus Striatum / Q000166:cytology / Q000502:physiology*; D003913:Dextroamphetamine / Q000494:pharmacology; D004567:Electrodes, Implanted; D004594:Electrophysiology; D008297:Male; D009043:Motor Activity; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D011916:Rats, Inbred F344
D000697:Central Nervous System Stimulants; D003913:Dextroamphetamine