Long latency event-related potentials in rats: effects of dopaminergic and serotonergic depletions.
The effects of serotonergic and dopaminergic depletions on event-related potentials (ERPs) generated by an auditory "oddball" paradigm were evaluated. Eighteen rats received either sham or six-hydroxydopamine (6-OHDA) lesions to the ventral tegmental area (VTA), and were subsequently implanted with electrodes in the frontal cortex, dorsal hippocampus (DHPC), and amygdala (AMYG). In these animals, a series of large amplitude potentials in the 10-200 ms latency range could be recorded from all the brain areas tested. In addition, late positivities (in the 300-400 ms range) were identified in DHPC and AMYG. 6-OHDA lesions to the VTA were found to produce a 30-46% reduction in dopamine, but did not significantly alter any of the ERP components. A second series of rats were implanted with electrodes in cortex and DHPC. These rats then received vehicle injections and subsequently injections of parachlorophenylalanine (PCPA). PCPA produced a 50% depletion of serotonin concomitant with significant reductions in the negative components in the 50-100 ms range recorded in hippocampus and cortex. These studies support a role for serotonin but not dopamine in the processing of passively presented auditory stimuli and further suggest that the rat may be a good model for the exploration of long latency ERPs.
Ehlers
C L
CL
Department of Neuropharmacology, BCR-1, Research Institute of the Scripps Clinic, La Jolla, CA 92037.
Wall
T L
TL
Chaplin
R I
RI
D000679:Amygdala / Q000187:drug effects / Q000502:physiology; D000818:Animals; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology; D004298:Dopamine / Q000502:physiology*; D004594:Electrophysiology; D005072:Evoked Potentials, Auditory / Q000187:drug effects / Q000502:physiology*; D010134:Fenclonine / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology*
D012701:Serotonin; D010134:Fenclonine; D004298:Dopamine