Intrathecal apelin-13 produced different actions in formalin test and tail-flick test in mice.
Apelin was identified as natural ligand for APJ, a G protein-coupled receptor. APJ is expressed in spinal cord and dorsal root ganglion. This study was designed to investigate the effects and mechanisms of intrathecally (i.t.) administered apelin-13 on nociceptive response in formalin test and tail-flick test. In formalin test, i.t. injection of apelin-13 (0.3-3 nmol/mouse) had no effect on the nociceptive response in either acute phase (0-10 min) or interphase (10-20 min), but significantly produced hyperalgesic effect in late phase (20-30 min) at the dose of 3 nmol/mouse. The APJ receptor antagonist apelin-13(F13A) and GABAA receptor antagonist bicuculline methiodide, but not opioid receptor antagonist naloxone, significantly blocked the hyperalgesia caused by apelin-13 in late phase, indicating that i.t. apelin-13- induced hyperalgesia was mediated by APJ and GABAA receptor, rather than opioid receptor. However, in tail-flick test, i.t. injected apelin-13 (1 and 3 nmol/mouse) induced a significant antinociceptive effect, which was significantly antagonized by apelin-13(F13A) and naloxone, suggesting APJ and opioid receptor were involved in the antinociception of spinal apelin-13.
Institute of Biochemistry and Molecular Biology, School of Life Sciences, Lanzhou University, 222 Tianshui South Road, Lanzhou, Gansu 730000, China.
Shuang- Yu
S
Lv
Yan Jie
YJ
Yang
Shangyu
S
Hong
Ning- Bo
N
Wang
Yao- Jun
Y
Qin
Wei- Xin
W
Li
Qiang
Q
Chen
D000595:Amino Acid Sequence; D000818:Animals; D000075244:Apelin Receptors; D007278:Injections, Spinal; D036341:Intercellular Signaling Peptides and Proteins / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009270:Naloxone / Q000494:pharmacology / Q000627:therapeutic use; D009292:Narcotic Antagonists; D010146:Pain / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology*; D010147:Pain Measurement; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism; D011957:Receptors, Opioid / Q000627:therapeutic use; D013116:Spinal Cord / Q000187:drug effects
D000075244:Apelin Receptors; C491285:Aplnr protein, mouse; D036341:Intercellular Signaling Peptides and Proteins; D009292:Narcotic Antagonists; D043562:Receptors, G-Protein-Coupled; D011957:Receptors, Opioid; C495199:apelin-13 peptide; D009270:Naloxone