Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
8348771 | Peptides | 2013 | 7 Pages |
Abstract
Ghrelin, an acylated peptide produced in the stomach, increases food intake and growth hormone secretion, inhibits pro-inflammatory cascade, etc. Ghrelin and its receptor (GHS-R1a) mRNA were found in the area related to the regions for controlling pain transmission, such as the hypothalamus, the midbrain, the spinal cord, etc. Ghrelin has been shown to have antinociceptive activity and also anti-inflammatory properties in inflammatory pain and chronic neuropathic pain. Therefore, the aim of the present study was to investigate the effects of ghrelin for the first time in the acute pain modulation at the supraspinal level, using the tail withdrawal test and hot-plate test in mice. Intracerebroventricular (i.c.v.) administration of ghrelin (mouse, 0.1-3Â nmol) produced a dose- and time-related antinociceptive effect in the tail withdrawal test and hot-plate test, respectively. Antinociceptive effect elicited by ghrelin (i.c.v., 1Â nmol) was significantly antagonized by opioid receptor antagonist naloxone (i.c.v., 10Â nmol co-injection or i.p., 10Â mg/kg, 10Â min prior to ghrelin) in both tail withdrawal test and hot-plate test. At these doses, naloxone significantly antagonized the antinociceptive effect induced by morphine (i.c.v., 3Â nmol). Ghrelin (i.c.v., 1Â nmol)-induced antinociception was significantly antagonized by co-injection with 10Â nmol [d-Lys3]-GHRP-6, the selective antagonist of GHS-R1a identified more recently, while [d-Lys3]-GHRP-6 (10Â nmol) alone induced neither hyperalgesia nor antinociception. Overall this data indicate that ghrelin could produce antinociception through an interaction with GHS-R1a and with the central opioid system. Thus ghrelin may be a promising peptide for developing new analgesic drugs.
Related Topics
Life Sciences
Biochemistry, Genetics and Molecular Biology
Biochemistry
Authors
Jie Wei, Xing Zhi, Xiao-lang Wang, Ping Zeng, Ting Zou, Bei Yang, Jing-lei Wang,