Haloperidol regulates the phosphorylation level of the MEK-ERK-p90RSK signal pathway via protein phosphatase 2A in the rat frontal cortex

• Published in: The international journal of neuropsychopharmacology 2008-06, Vol.11 (4), p.509-517
• Main Authors: Kim, Se Hyun, Seo, Myoung Suk, Jeon, Won Je, Yu, Hyun-Sook, Park, Hong Geun, Jung, Gyung-Ah, Lee, Hee Young, Kang, Ung Gu, Kim, Yong Sik
• Format: Article
• Language: English
• Subjects: Animals; Antipsychotic Agents - pharmacology; Blotting, Western; Dose-Response Relationship, Drug; Extracellular Signal-Regulated MAP Kinases - genetics; Extracellular Signal-Regulated MAP Kinases - physiology; Haloperidol - pharmacology; Immunoprecipitation; Kinases; Male; Mitogen-Activated Protein Kinases - genetics; Mitogen-Activated Protein Kinases - physiology; Phosphoprotein Phosphatases - metabolism; Phosphorylation - drug effects; Prefrontal Cortex - drug effects; Prefrontal Cortex - enzymology; Prefrontal Cortex - physiology; Protein Phosphatase 2 - physiology; Proteins; Proto-Oncogene Proteins c-raf - genetics; Proto-Oncogene Proteins c-raf - physiology; Psychotropic drugs; raf Kinases - physiology; Rats; Rats, Sprague-Dawley; Ribosomal Protein S6 Kinases, 90-kDa - genetics; Ribosomal Protein S6 Kinases, 90-kDa - physiology; Rodents; Signal Transduction - drug effects
• ISSN: 1461-1457; 1469-5111
• DOI: 10.1017/S1461145707008292

Haloperidol, a classical antipsychotic drug, affects the extracellular signal-regulated kinase (ERK) pathway in the brain. However, findings are inconsistent and the mechanism by which haloperidol regulates ERK is poorly understood. Therefore, we examined the ERK pathway and the related protein phosphatase 2A (PP2A) in detail after haloperidol administration. Haloperidol (0.5 and 1 mg/kg) induced biphasic changes in the phosphorylation level of mitogen-activated protein kinase kinase (MEK), ERK, and p90 ribosomal S6 kinase (p90RSK) without changing Raf-1 phosphorylation. Fifteen minutes after haloperidol administration, MEK-ERK-p90RSK phosphorylation increased, whilst PP2A activity decreased. At 60 min, the reverse was observed and the binding of PP2A to MEK and ERK increased. Higher dosages of haloperidol (2 and 4 mg/kg), affected neither MEK-ERK-p90RSK phosphorylation nor PP2A activity. Accordingly, PP2A regulates acute dose- and time-dependent changes in MEK-ERK-p90RSK phosphorylation after haloperidol treatment. These findings suggest the involvement of a dephosphorylating mechanism in the acute action of haloperidol.