title: The α1 adrenoceptors in ventrolateral orbital cortex contribute to the expression of morphine-induced behavioral sensitization in rats.
abstract: The aim of the present study was to investigate the effect of microinjection of benoxathian, selective α1 adrenoceptor antagonist, into the ventrolateral orbital cortex (VLO) on morphine-induced behavioral sensitization and its underlying molecular mechanism in rats. A single morphine treatment protocol was used in establishing the behavioral sensitization model. The effect of bilateral intra-VLO benoxathian injection on locomotor activity was examined and the protein expression levels of α1 adrenoceptors and activation of extracellular signal-regulated kinase (ERK) in the VLO were detected after locomotor test. The results showed that a single injection of morphine could induce behavioral sensitization by a low challenge dosage of morphine after a 7-days drug free period. Benoxathian significantly suppressed the expression but not the development of morphine-induced behavioral sensitization. Morphine treatment significantly elicited ERK phosphorylation and downregulated the expression level of α1 adrenoceptors in the VLO. In addition, intra-VLO benoxathian injection enhanced the expression levels of α1 adrenoceptors and phosphorylated ERK. These results suggest that α1 adrenoceptors in the VLO are involved in regulating the expression of morphine-induced behavioral sensitization. The effect of decreased locomotor activity by blocking α1 adrenoceptors might be associated with activation of ERK in the VLO.
authors.affiliation: College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Division of Forensic Medicine, School of Basic Medical Sciences, Hubei University of Medicine, Shiyan, Hubei 442000, China.
authors.forename: Lai
authors.initials: L
authors.lastname: Wei
authors.affiliation: College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China.
authors.forename: Yuan-Mei
authors.initials: YM
authors.lastname: Zhu
authors.affiliation: College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China.
authors.forename: Yu-Xiang
authors.initials: YX
authors.lastname: Zhang
authors.affiliation: College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China.
authors.forename: Feng
authors.initials: F
authors.lastname: Liang
authors.affiliation: College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China.
authors.forename: Teng
authors.initials: T
authors.lastname: Li
authors.affiliation: College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China.
authors.forename: Hong-Yu
authors.initials: HY
authors.lastname: Gao
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China. Electronic address: huofq@mail.xjtu.edu.cn.
authors.forename: Fu-Quan
authors.initials: FQ
authors.lastname: Huo
authors.affiliation: College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi 710061, China; Key Laboratory of Environment and Genes Related to Diseases (Xi'an Jiaotong University), Ministry of Education, China. Electronic address: yanchunxia@mail.xjtu.edu.cn.
authors.forename: Chun-Xia
authors.initials: CX
authors.lastname: Yan
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009043:Motor Activity / Q000187:drug effects*; D009294:Narcotics / Q000494:pharmacology*; D010075:Oxathiins / Q000494:pharmacology; D010766:Phosphorylation; D017397:Prefrontal Cortex / Q000187:drug effects / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D018340:Receptors, Adrenergic, alpha-1 / Q000378:metabolism*
chemical_list: D000317:Adrenergic alpha-Antagonists; D009294:Narcotics; D010075:Oxathiins; D018340:Receptors, Adrenergic, alpha-1; D009020:Morphine; C050877:benoxathian; D048049:Extracellular Signal-Regulated MAP Kinases
keywords: Behavioral sensitization; Extracellular signal-regulated kinase; Morphine; Ventrolateral orbital cortex; α(1) adrenoceptor