title: Acute immediate-early gene response to 6-hydroxydopamine infusions into the medial forebrain bundle.
abstract: Although the long-term neurobiological and behavioral effects of nigrostriatal lesions are well characterized, the events occurring soon after injury are not. These acute events can provide insight into the mechanisms underlying long-term adaptations to nigrostriatal lesions. The present experiments examined the basal ganglia immediate-early gene response to infusions of the catecholamine neurotoxin 6-hydroxydopamine into the nigrostriatal pathway in rats. Following 6-hydroxydopamine infusions into the medial forebrain bundle in awake, behaving rats, there was a rapid and transient induction of striatal c-fos and zif/268 messenger RNAs. Both immediate-early genes were maximally induced by 45min post-infusion, and returned to control levels by 1.5h (c-fos) or 3h (zif/268) post-infusion. Double-labeling experiments revealed that striatal c-fos expression occurred preferentially in preproenkephalin-expressing neurons. 6-Hydroxydopamine-induced c-fos messenger RNA was also observed in the substantia nigra pars reticulata and entopeduncular nucleus, but not the globus pallidus, 45 min after medial forebrain bundle 6-hydroxydopamine infusions. Finally, the role of ionotropic striatal glutamate receptors in nigrostriatal injury-induced striatal c-fos was examined by combining medial forebrain bundle 6-hydroxydopamine infusions with intrastriatal glutamate antagonist infusions. Both the N-methyl-D-aspartate antagonist, (+/-)-3-(2-carboxypiperazin-4-yl)-propyl-1-phosphonic acid, and the non-N-methyl-D-aspartate antagonist, 6,7-dinitroquinoxaline-2, 3-dione, blocked striatal induction of c-fos messenger RNA following 6-hydroxydopamine infusions into the medial forebrain bundle. These results provide evidence of rapidly developing, glutamate-dependent molecular responses in the basal ganglia which may contribute to some of the well-described long-term adaptations of this system to nigrostriatal injury.
authors.affiliation: Department of Neurobiology and Behavior, University of California, Irvine 92697-4550, USA.
authors.forename: J J
authors.initials: JJ
authors.lastname: Schuller
authors.forename: J F
authors.initials: JF
authors.lastname: Marshall
mesh_terms: D000818:Animals; D001479:Basal Ganglia / Q000378:metabolism; D001522:Behavior, Animal; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D015870:Gene Expression; D017781:Genes, Immediate-Early / Q000235:genetics*; D008297:Male; D008474:Medial Forebrain Bundle / Q000187:drug effects* / Q000473:pathology / Q000503:physiopathology*; D009043:Motor Activity; D016627:Oxidopamine / Q000494:pharmacology*; D010879:Piperazines / Q000494:pharmacology; D011810:Quinoxalines / Q000494:pharmacology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012677:Sensation; D013997:Time Factors
chemical_list: D018691:Excitatory Amino Acid Antagonists; D010879:Piperazines; D011810:Quinoxalines; D012333:RNA, Messenger; C056723:FG 9041; D016627:Oxidopamine; C050592:3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid