RT Journal Article
SR Electronic
T1 Quantification of Phosphorylated cAMP-Response Element-Binding Protein Expression throughout the Brain of Amphetamine-Sensitized Rats: Activation of Hypothalamic Orexin A-Containing Neurons
JF Journal of Pharmacology and Experimental Therapeutics
JO J Pharmacol Exp Ther
FD American Society for Pharmacology and Experimental Therapeutics
SP 805
OP 812
DO 10.1124/jpet.107.125732
VO 323
IS 3
A1 Cameron S. McPherson
A1 Travis Featherby
A1 Elena Krstew
A1 J. Lawrence Andrew
YR 2007
UL http://jpet.aspetjournals.org/content/323/3/805.abstract
AB In the present study, using rats, we have examined acute, contextual, and sensitized patterns of activated or phosphorylated cAMP response element-binding protein (pCREB) expression in parallel, assaying across multiple nuclei that have been implicated in addiction. The paradigm used included a comparison of pretreatment dose of amphetamine upon patterns of cellular activation, following rechallenge. Because efferent orexinergic projections synapse on many targets through the mammalian brain, including mesotelencephalic regions and limbic systems involved in drug reward and reinforcement, we examined for coexpression of pCREB or c-Fos double labeling within orexin A-immunopositive neurons following sensitization. Acute challenge with amphetamine (1.5 mg/kg i.p.) resulted in an increase in the number of pCREB-immunoreactive (-IR) cells within the substantia nigra but a decrease of pCREB-IR cells in the central and medial subnuclei of the amygdala. Contextual re-exposure to the drug treatment environment altered pCREB expression, particularly in the basal ganglia and hypothalamus, although these effects were dictated by pretreatment dose of amphetamine. Sensitization to amphetamine resulted in robust increases in pCREB-IR cell numbers in the basal ganglia and lateral septum of rats that had been pretreated with high-dose (10 mg/kg i.p.) but not low-dose (2 mg/kg i.p.) amphetamine, despite a similar behavioral response. Orexin A-containing cells in the hypothalamus of sensitized rats did not coexpress pCREB; however, these cells double-labeled for c-Fos and orexin A. These data suggest that orexinergic neurons are activated during the expression of behavioral sensitization, although in a heterogenous manner with regard to afferent topologies and functional roles in the nervous system. The American Society for Pharmacology and Experimental Therapeutics