title: Long-term effects of dopamine-depleting brain lesions on spontaneous activity of type II striatal neurons: relation to behavioral recovery.
abstract: The long-term effects of dopamine (DA)-depleting brain lesions on behavior and spontaneous activity of Type II striatal neurons were measured in rats after intraventricular injection of the neurotoxin 6-hydroxydopamine (6-OHDA). Spontaneous firing rates were increased relative to control values when recorded 4-8 days or 4-6 weeks postlesion in animals displaying aphagia, adipsia and akinesia. In contrast, spontaneous activity was not increased when recorded 4-6 weeks after the lesion in animals that had recovered from behavioral deficits. Other animals that had recovered from the effects of an earlier 6-OHDA treatment were given either a second injection of 6-OHDA or a systemic injection of haloperidol, a DA receptor antagonist. In both groups, discharge rates were elevated relative to control levels in association with a reinstatement of behavioral deficits. These results demonstrate that behavioral recovery after large DA-depleting brain lesions is associated with a return of spontaneous activity of striatal neurons to normal levels, and suggest that both behavioral and electrophysiological measures are dependent on the functioning of residual elements of the DA system.
mesh_terms: D000200:Action Potentials; D000818:Animals; D001927:Brain Diseases / Q000139:chemically induced / Q000503:physiopathology*; D003342:Corpus Striatum / Q000032:analysis / Q000503:physiopathology*; D004298:Dopamine / Q000032:analysis; D006220:Haloperidol / Q000494:pharmacology; D006892:Hydroxydopamines / Q000494:pharmacology; D008297:Male; D009043:Motor Activity / Q000502:physiology; D016627:Oxidopamine; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D006892:Hydroxydopamines; D016627:Oxidopamine; D006220:Haloperidol; D004298:Dopamine