Acute treatment with the N-methyl-D-aspartate receptor antagonist MK-801: effect of concurrent administration of haloperidol or scopolamine on preproenkephalin mRNA levels of the striatum and nucleus accumbens of the rat brain.
We injected rats three times at 3 h intervals (from 0900 h to 1500 h) with the N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 at 0.1 or 0.5 mg/kg of body weight. Three hours after the last injection, animals were sacrificed and the brains were processed for in situ hybridization histochemistry. Preproenkephalin (PPE) mRNA levels were significantly decreased throughout the caudate-putamen (CPu) and nucleus accumbens (NAc) at the lower dose. The higher dose produced significant decreases only in anterior CPu (aCPu) and NAc. Concurrent administration of the muscarinic cholinergic receptor antagonist scopolamine at 2 or 5 mg/kg neither potentiated nor prevented the effect of MK-801 on PPE mRNA levels in the neostriatum. In contrast, co-administration of haloperidol (dopamine receptor antagonist) with MK-801 blocked the effect of the latter in the NAc, and elevated PPE mRNA levels throughout the CPu. The data demonstrate that the acute effects of glutamate receptor activity on striatal and accumbal PPE mRNA expression via the NMDA receptor can be modulated by the dopaminergic system in the brain of the rat.
Noailles
P A
PA
Department of Biological Sciences, Hunter College of the City University of New York, NY 10021, USA.
Villegas
M
M
Ledoux
M
M
Lucas
L R
LR
McEwen
B S
BS
Angulo
J A
JA
D000818:Animals; D001483:Base Sequence; D001923:Brain Chemistry / Q000187:drug effects; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D018492:Dopamine Antagonists / Q000494:pharmacology*; D004745:Enkephalins / Q000096:biosynthesis; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology*; D006220:Haloperidol / Q000494:pharmacology*; D017403:In Situ Hybridization; D008297:Male; D008969:Molecular Sequence Data; D018727:Muscarinic Antagonists / Q000494:pharmacology*; D017072:Neostriatum / Q000187:drug effects / Q000378:metabolism; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D011498:Protein Precursors / Q000096:biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D012601:Scopolamine / Q000494:pharmacology*
D018492:Dopamine Antagonists; D004745:Enkephalins; D018691:Excitatory Amino Acid Antagonists; D018727:Muscarinic Antagonists; D011498:Protein Precursors; D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; C033660:preproenkephalin; D012601:Scopolamine; D006220:Haloperidol