title: Differential and region-specific activation of mitogen-activated protein kinases following chronic administration of phencyclidine in rat brain.
abstract: We have previously demonstrated elevation of the extracellular signal-regulated kinase (ERK) pathway in the cerebellum from patients with schizophrenia, an illness that may involve dysfunction of the N-methyl-D-aspartate (NMDA) receptor. Since the NMDA antagonist, phencyclidine (PCP), produces schizophrenic-like symptoms in humans, and abnormal behavior in animals, we examined the effects of chronic PCP administration in time- and dose-dependent manner on ERK and two other members of mitogen-activated protein kinase family, c-Jun N-terminal protein kinase (JNK) and p38, in rat brain. Osmotic pumps for PCP (18 mg/kg/day) and saline (controls) were implanted subcutaneously in rats for three, 10, and 20 days. Using Western blot analysis, we found no change at three days, but a significant increase in the phosphorylation of ERK1, ERK2 and MEK in the cerebellum at 10- and 20-days of continuous PCP infusion. For the experiments involving various doses of PCP, rats were infused with PCP at concentrations of 2.5, 10, 18, or 25 mg/kg/day, or saline for 10 days. We observed a dose-dependent elevation in the phosphorylation of ERK1 and ERK2 only in the cerebellum but not in brainstem, frontal cortex or hippocampus. The activities of JNK and p38 were unchanged in all investigated brain regions including cerebellum. These results demonstrate that chronic infusion of PCP in rats produces a differential and brain region-specific activation of MAP kinases, suggesting a role for the ERK signaling pathway in PCP abuse and perhaps in schizophrenia.
authors.affiliation: Departments of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, USA.
authors.forename: S V
authors.initials: SV
authors.lastname: Kyosseva
authors.forename: S M
authors.initials: SM
authors.lastname: Owens
authors.forename: A D
authors.initials: AD
authors.lastname: Elbein
authors.forename: C N
authors.initials: CN
authors.lastname: Karson
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000201:enzymology*; D001933:Brain Stem / Q000187:drug effects / Q000201:enzymology; D002531:Cerebellum / Q000187:drug effects / Q000201:enzymology; D048031:JNK Mitogen-Activated Protein Kinases; D008099:Liver / Q000187:drug effects / Q000201:enzymology; D048670:MAP Kinase Kinase 4; D008297:Male; D020929:Mitogen-Activated Protein Kinase Kinases / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000502:physiology*; D009995:Osmosis; D010622:Phencyclidine / Q000008:administration & dosage / Q000493:pharmacokinetics / Q000633:toxicity*; D010623:Phencyclidine Abuse; D017397:Prefrontal Cortex / Q000187:drug effects / Q000201:enzymology; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000187:drug effects; D012559:Schizophrenia / Q000139:chemically induced / Q000201:enzymology* / Q000503:physiopathology*; D015398:Signal Transduction; D048051:p38 Mitogen-Activated Protein Kinases
chemical_list: D016194:Receptors, N-Methyl-D-Aspartate; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048670:MAP Kinase Kinase 4; D020929:Mitogen-Activated Protein Kinase Kinases; D010622:Phencyclidine