title: Differential effects of cocaine on extracellular signal-regulated kinase phosphorylation in nuclei of the extended amygdala and prefrontal cortex of psychogenetically selected Roman high- and low-avoidance rats.
abstract: Roman high (RHA)- and low (RLA)-avoidance rats are selectively bred for rapid vs. poor acquisition of active avoidance, respectively, and differ markedly in emotional reactivity, coping style, and behavioral and neurochemical responses to morphine and psychostimulants. Accordingly, acute cocaine induces more robust increments in locomotion and dopamine output in the nucleus accumbens shell (AcbSh) of RHA than of RLA rats. Cocaine induces short- and long-term neuronal plasticity via activation of the extracellular signal-regulated kinase (ERK) pathway. This study compares the effects of acute cocaine on ERK phosphorylation (pERK) in limbic brain areas of Roman rats. In RHA but not RLA rats, cocaine (5 mg/kg) increased pERK in the infralimbic prefrontal cortex and AcbSh, two areas involved in its acute effects, but did not modify pERK in the prelimbic prefrontal cortex and Acb core, which mediate the chronic effects of cocaine. Moreover, cocaine failed to affect pERK immunolabeling in the bed nucleus of stria terminalis pars lateralis and central amygdala of either line but increased it in the basolateral amygdala of RLA rats. These results extend to pERK expression previous findings on the greater sensitivity to acute cocaine of RHA vs. RLA rats and confirm the notion that genetic factors influence the differential responses of the Roman lines to addictive drugs. Moreover, they support the view that the Roman lines are a useful tool to investigate the molecular underpinnings of individual vulnerability to drug addiction.
authors.affiliation: Department of Life and Environmental Sciences, University of Cagliari, Cagliari, Italy.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Giorgi
authors.forename: Maria G
authors.initials: MG
authors.lastname: Corda
authors.forename: Marta
authors.initials: M
authors.lastname: Sabariego
authors.forename: Valentina
authors.initials: V
authors.lastname: Giugliano
authors.forename: Maria A
authors.initials: MA
authors.lastname: Piludu
authors.forename: Michela
authors.initials: M
authors.lastname: Rosas
authors.forename: Elio
authors.initials: E
authors.lastname: Acquas
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects* / Q000502:physiology; D066274:Central Amygdaloid Nucleus / Q000187:drug effects* / Q000201:enzymology; D003042:Cocaine / Q000494:pharmacology*; D018765:Dopamine Uptake Inhibitors / Q000494:pharmacology*; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000235:genetics; D008297:Male; D010766:Phosphorylation / Q000187:drug effects; D017397:Prefrontal Cortex / Q000187:drug effects* / Q000201:enzymology; D051381:Rats; D011919:Rats, Inbred Strains / Q000502:physiology
chemical_list: D018765:Dopamine Uptake Inhibitors; D048049:Extracellular Signal-Regulated MAP Kinases; D003042:Cocaine
keywords: Roman high- and low-avoidance rats; extracellular signal-regulated kinase (ERK); nucleus accumbens; prefrontal cortex; psychogenetic selection