The ability of amphetamine to evoke arc (Arg 3.1) mRNA expression in the caudate, nucleus accumbens and neocortex is modulated by environmental context.
The ability of amphetamine or cocaine to induce the expression of c-fos mRNA in a number of brain regions is greatly enhanced when these drugs are administered in a distinct and relatively novel environment, relative to when they are given in the home cage. The purpose of this study was to determine if environmental context has a similar effect on the ability of amphetamine to induce the expression of arc (also known as Arg 3.1), an "effector" immediate early gene (IEG) thought to play a direct role in cellular plasticity. Rats were administered either saline or amphetamine (0.5 mg/kg, i.v.), in their home cage or in a distinct test environment. Fifty minutes later, they were decapitated and their brains processed for in situ hybridization histochemistry. In the prefrontal cortex, caudate-putamen and core of the nucleus accumbens, amphetamine significantly increased arc mRNA expression under both conditions, but the level of expression was significantly enhanced when amphetamine was given in a distinct environment. In the shell of the nucleus accumbens amphetamine significantly increased the expression of arc mRNA only when it was administered in the distinct environment. Thus, the ability of amphetamine to induce the expression of arc varies as a function of the environmental context in which it is administered. This could contribute to the ability of environmental context to modulate forms of drug experience-dependent neuroplasticity, including behavioral sensitization.
Klebaur
Jennifer E
JE
Biopsychology and Neuroscience Programs, Department of Psychology, East Hall, 525 East University Street, Ann Arbor, MI 48109-1109, USA.
Ostrander
Michelle M
MM
Norton
Camille S
CS
Watson
Stanley J
SJ
Akil
Huda
H
Robinson
Terry E
TE
D000661:Amphetamine / Q000494:pharmacology*; D000818:Animals; D051017:Apoptosis Regulatory Proteins; D001923:Brain Chemistry / Q000187:drug effects*; D002421:Caudate Nucleus / Q000187:drug effects / Q000378:metabolism; D000697:Central Nervous System Stimulants / Q000494:pharmacology*; D004777:Environment; D017403:In Situ Hybridization; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis / Q000235:genetics*; D019579:Neocortex / Q000187:drug effects / Q000378:metabolism; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism; D012333:RNA, Messenger / Q000096:biosynthesis*; D051381:Rats; D017207:Rats, Sprague-Dawley
D051017:Apoptosis Regulatory Proteins; D000697:Central Nervous System Stimulants; D009124:Muscle Proteins; C491788:Nol3 protein, rat; D012333:RNA, Messenger; D000661:Amphetamine