Dexmedetomidine increases acetylation level of histone through ERK1/2 pathway in dopamine neuron.

Dexmedetomidine is a highly selective α2-adrenoceptor agonist with sedation, anesthetic sparing, analgesia, sympatholytic, and neuroprotective properties. This study evaluated neuroprotective effects of dexmedetomidine on dopamine neurons correlated to histone acetylation via extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) pathway. Animals were randomly assigned to four groups and treatments were given as onetime doses: dimethyl sulfoxide (DMSO; n = 6), dexmedetomidine 1 mg/kg ( n = 6), 10 mg/kg ( n = 6), and 100 mg/kg ( n = 6). Acetylation histone protein levels and ERK protein levels in rats dopamine neuron from striatum were determined by Western blotting after various doses of dexmedetomidine (1, 10, and 100 mg/kg) treatments. The messenger RNA expression related to signal transduction coupled to 5-hydroxytryptamine receptor (5-HTR) in striatum was assessed by quantitative real-time polymerase chain reaction (qRT-PCR) analysis. Dexmedetomidine administration increased expression of ERK1/2 phosphorylation and histones H3 acetylation. PD098059, an inhibitor of pERK1/2, almost completely blocked dexmedetomidine-induced histones H3 acetylation. In addition, bioinformatics analysis in combination with qRT-PCR demonstrated that dexmedetomidine could regulate the genes that are related to signal transduction coupled to 5-HTR via α2-adrenoceptor. Our results define dexmedetomidine as a modulator of histones H3 acetylation via ERK1/2 signaling pathway in dopamine neuron from striatum, which may provide clues for the mechanism underlying the neuroprotective effects of dexmedetomidine.