Amylin suppresses acetic acid-induced visceral pain and spinal c-fos expression in the mouse.
Amylin is a member of calcitonin or calcitonin gene-related peptide (CGRP) family. Immunohistochemical study revealed a dense network of amylin-immunoreactive (irAMY) cell processes in the superficial dorsal horn of the mice. Numerous dorsal root ganglion (DRG) and trigeminal ganglion cells expressed moderate to strong irAMY. Reverse transcriptase-polymerase chain reaction (RT-PCR) revealed amylin receptor mRNA in the mouse spinal cord, brain stem, cortex, hypothalamus and hippocampus. The nociceptive or antinociceptive effects of amylin were evaluated in the acetic acid-induced writhing test. Amylin (0.1, 0.5 and 1 mg/kg, intraperitoneally (i.p.) or 1-10 microg, intrathecally (i.t.)) reduced the number of writhes in a dose-dependent manner. Pretreatment of the mice with the amylin receptor antagonist salmon calcitonin (8-32), either by i.p. or i.t., antagonized the effect of amylin on acetic acid-induced writhing test. Locomotor activity was not significantly modified by amylin injected either i.p. (0.01-1 mg/kg) or i.t. (1-10 microg). Measurement of c-fos mRNA by RT-PCR or proteins by Western blot showed that the levels were upregulated in the spinal cord of mice injected with acetic acid and the increase was attenuated by pretreatment with amylin (10 microg, i.t.). Collectively, our result demonstrates that irAMY is expressed in DRG neurons with their cell processes projecting to the superficial layers of the dorsal horn, and that the peptide by interacting with amylin receptors in the spinal cord may be antinociceptive.
Huang
X
X
Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140, USA. huangxf@temple.edu
Yang
J
J
Chang
J K
JK
Dun
N J
NJ
D019342:Acetic Acid; D000682:Amyloid / Q000008:administration & dosage / Q000494:pharmacology*; D000700:Analgesics / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002116:Calcitonin / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D058228:Islet Amyloid Polypeptide; D008124:Locomotion / Q000187:drug effects; D008297:Male; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008813:Mice, Inbred ICR; D010146:Pain / Q000139:chemically induced / Q000188:drug therapy* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D058261:Receptor Activity-Modifying Proteins; D018003:Receptors, Calcitonin / Q000378:metabolism; D058287:Receptors, Islet Amyloid Polypeptide; D018000:Receptors, Peptide / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D014781:Viscera / Q000187:drug effects*
D000682:Amyloid; D000700:Analgesics; D047908:Intracellular Signaling Peptides and Proteins; D058228:Islet Amyloid Polypeptide; D008565:Membrane Proteins; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D058261:Receptor Activity-Modifying Proteins; D018003:Receptors, Calcitonin; D058287:Receptors, Islet Amyloid Polypeptide; D018000:Receptors, Peptide; C028815:salmon calcitonin; D002116:Calcitonin; D019342:Acetic Acid