Involvement of the nucleus accumbens-ventral pallidal pathway in postictal behavior induced by a hippocampal afterdischarge in rats.
The hypothesis that postictal motor behaviors induced by a hippocampal afterdischarge (AD) are mediated by a pathway through the nucleus accumbens (NAC) and ventral pallidum (VP) was evaluated in freely moving rats. Tetanic stimulation of the hippocampal CA1 evoked an AD of 15-30 s and an increase in number of wet-dog shakes, face washes, rearings and locomotor activity. Bilateral injection of haloperidol (5 micrograms/side) or the selective dopamine D2 receptor antagonist, (+/-)-sulpiride (200 ng/side) before the hippocampal AD, into the NAC selectively reduced rearings and locomotor activity, but not the number of wet-dog shakes and face washes. Injection of R(+)-SCH-23390 (1 microgram/side), a D1 receptor antagonist, or rimcazole (0.4 mg/side), a sigma opioid receptor antagonist, into the NAC did not significantly alter postictal behaviors. Bilateral injection of muscimol (1 ng/side), a gamma-aminobutyric acid (GABAA) receptor agonist, into the VP before the AD significantly blocked all postictal behaviors. It is concluded that postictal locomotor activity induced by a hippocampal AD is mediated by activation of dopamine D2 receptors in the NAC and a pathway through the VP.
Ma
J
J
Department of Physiology, University Hospital, University of Western Ontario, London, Canada.
Brudzynski
S M
SM
Leung
L W
LW
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology*; D018492:Dopamine Antagonists / Q000494:pharmacology; D065127:Dopamine D2 Receptor Antagonists; D004558:Electric Stimulation; D004833:Epilepsy, Temporal Lobe / Q000503:physiopathology*; D019054:Evoked Potentials, Motor / Q000187:drug effects / Q000502:physiology*; D018755:GABA Agonists / Q000494:pharmacology; D005917:Globus Pallidus / Q000187:drug effects / Q000502:physiology*; D006220:Haloperidol / Q000494:pharmacology; D006624:Hippocampus / Q000187:drug effects / Q000502:physiology*; D008297:Male; D009118:Muscimol / Q000494:pharmacology; D009434:Neural Pathways / Q000187:drug effects / Q000502:physiology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000502:physiology*; D051381:Rats; D017447:Receptors, Dopamine D1 / Q000037:antagonists & inhibitors
D018492:Dopamine Antagonists; D065127:Dopamine D2 Receptor Antagonists; D018755:GABA Agonists; D017447:Receptors, Dopamine D1; D009118:Muscimol; D006220:Haloperidol