Post-training intra-striatal scopolamine or flupenthixol impairs radial maze learning in rats.
Systemic treatments with acetylcholine (ACh) or dopamine (DA) receptor antagonists during hours 0-4 but not during hours 5-8 following training on a radial arm maze (RAM) or lesions of the dorsal striata impair learning. This suggested that intra-striatal infusions of ACh or DA receptor antagonists during hours 0-4 following training may impair learning. Rats were randomly assigned to groups (ns=5-11) receiving dorsal striatal infusions of the ACh receptor antagonist scopolamine (0-18 microg/microL at 0 and 2h or at 4 and 6h after training), the DA receptor antagonist cis-flupenthixol (0-25 microg/microL at 0, 4 or 12h after training) or the inactive isomer trans-flupenthixol (6 microg/microL at 0 h after training). Scopolamine and cis-flupenthixol impaired the habit-learning version of the task. Given after hours 0-4 following training, the effects of scopolamine were diminished but those of cis-flupenthixol were not. Trans-flupenthixol produced less impairment than cis-flupenthixol. Results suggest that ACh and DA receptors in the dorsal striatum during hours 0-4 following training play a role in habit learning.
Department of Psychology, Queen's University, Kingston, Ont., Canada K7L 3N6. Glenn.Legault@sw.ca
Glenn
G
Legault
Carlyle T
CT
Smith
Richard J
RJ
Beninger
D000109:Acetylcholine / Q000502:physiology; D000818:Animals; D001921:Brain; D003342:Corpus Striatum / Q000187:drug effects* / Q000502:physiology; D004298:Dopamine / Q000502:physiology; D018492:Dopamine Antagonists / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D005475:Flupenthixol / Q000494:pharmacology*; D008297:Male; D018782:Maze Learning / Q000187:drug effects* / Q000502:physiology; D011939:Mental Recall / Q000187:drug effects / Q000502:physiology; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012601:Scopolamine / Q000494:pharmacology*; D012895:Sleep, REM / Q000187:drug effects / Q000502:physiology
D018492:Dopamine Antagonists; D018727:Muscarinic Antagonists; D012601:Scopolamine; D005475:Flupenthixol; D000109:Acetylcholine; D004298:Dopamine