Subthalamic nucleus cell firing in the 6-OHDA-treated rat: basal activity and response to haloperidol.
Single unit recordings from neurons of the subthalamic nucleus were made in control and 6-hydroxydopamine (6-OHDA)-treated rats anesthetized with chloral hydrate. Subthalamic nucleus cells in this preparation exhibited a wide range of firing rates and three different firing patterns. These patterns were defined as 'burst', 'normal', and 'mixed' based on comparisons of their interspike interval histograms. Four to 6 weeks after 6-OHDA treatment there was no change in the basal firing rates of subthalamic nucleus cells, but there was a significant shift in firing pattern, with a smaller proportion of cells exhibiting the 'normal' firing pattern. The response of subthalamic nucleus neurons to acute administration of haloperidol was also altered in 6-OHDA-treated rats tested 4-6 weeks post-lesion, with a significantly greater proportion of cells responding to doses of haloperidol as low as 0.2 mg/kg (i.v.) with increases in firing rate of 20% or more. These results suggest that the subthalamic nucleus is probably not involved in the increases in basal levels of dopamine cell activity observed previously in the 6-OHDA-treated rat, but may play a role in the acute induction of depolarization block of dopamine cell firing in response to haloperidol administration in this model.
Hollerman
J R
JR
Department of Behavioral Neuroscience, University of Pittsburgh, PA 15260.
Grace
A A
AA
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001481:Basal Metabolism / Q000187:drug effects*; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism; D004298:Dopamine / Q000378:metabolism*; D004558:Electric Stimulation; D005917:Globus Pallidus / Q000502:physiology; D006220:Haloperidol / Q000494:pharmacology*; D008297:Male; D009474:Neurons / Q000187:drug effects / Q000502:physiology; D016627:Oxidopamine / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013787:Thalamic Nuclei / Q000187:drug effects*
D016627:Oxidopamine; D006220:Haloperidol; D004298:Dopamine