title: The involvement of norepinephrine in pain modulation in the nucleus accumbens of morphine-dependent rats.
abstract: Opioids are effective analgesics used clinically for both acute and chronic pain management. However, repeated opioid treatment can induce serious side effects such as nausea, vomiting, drowsiness, respiratory depression, euphoria, dependence, hyperalgesia, and tolerance. The mechanism of noxious information transmission in the central nervous system following dependence is still not clear. Norepinephrine (NE), an important neurotransmitter, participates both in the process of opioid dependence and also pain modulation in the central nervous system. In this study, we examined the role of NE on the evoked discharges of pain-excitation neurons (PENs) and pain-inhibition neurons (PINs) in the nucleus accumbens (NAc) of rats, following the development of morphine dependence. Our results revealed that NE inhibited the evoked discharges of PENs and attenuated the inhibition of PINs, while phentolamine enhanced the evoked discharges of PENs and facilitated the inhibition of PINs. These results indicate that the inhibitory action of NE on pain modulation acts via alpha adrenoceptors in the NAc of morphine-dependent rats.
authors.affiliation: Department of Physiology, Harbin Medical University, Xuefu Road, No.194, Harbin 150081, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pediatrics of Second Affiliated Hospital, Harbin Medical University, Harbin 150081, PR China.
authors.forename: Hui
authors.initials: H
authors.lastname: Qu
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, 150081, PR China.
authors.forename: You
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: Department of Biochemistry and Molecular Biology, Harbin Medical University, 150081, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Physiology, Harbin Medical University, Xuefu Road, No.194, Harbin 150081, PR China.
authors.forename: Duo
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Basic Medicine, Heilongjiang Nursing College, Harbin 150080, PR China.
authors.forename: Xu
authors.initials: X
authors.lastname: Yang
authors.affiliation: Department of Neurology of Second Affiliated Hospital, Harbin Medical University, Harbin 150081, PR China. Electronic address: yangchunxiao72@163.com.
authors.forename: ChunXiao
authors.initials: C
authors.lastname: Yang
authors.affiliation: Department of Physiology, Harbin Medical University, Xuefu Road, No.194, Harbin 150081, PR China. Electronic address: manyingxu@sohu.com.
authors.forename: ManYing
authors.initials: M
authors.lastname: Xu
mesh_terms: D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000818:Animals; D004558:Electric Stimulation; D005071:Evoked Potentials; D008297:Male; D009021:Morphine Dependence / Q000378:metabolism* / Q000503:physiopathology; D009474:Neurons / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism* / Q000494:pharmacology; D009714:Nucleus Accumbens / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D010146:Pain / Q000378:metabolism / Q000503:physiopathology*; D010646:Phentolamine / Q000494:pharmacology; D017208:Rats, Wistar
chemical_list: D000317:Adrenergic alpha-Antagonists; D009638:Norepinephrine; D010646:Phentolamine
keywords: Analgesia; Dependence; Morphine; Norepinephrine; Nucleus accumbens