[Effect of ACTH on the expression of somatostatin and c-fos in the spinal cord and formalin evoked pain response].
In the present study, the effect of ACTH on the expression of somatostatin and c-fos in the spinal cord and formalin induced pain responses in rats were studied using immunohistochemistry and in situ hybridization. The results showed that subcutaneous injection of formalin in the right hindpaw increased c-fos-like immunoreactivity (FLI), somatostatin-like immunoreactivity (Som-LI), Som-LI/FLI and perprosomatostatin mRNA (PPS-mRNA) in neurones of right spinal dorsal horn and significantly enhanced pain intensity rating. ACTH decreased the FLI,Som-LI, Som-LI/FLI and PPS-mRNA levels of the spinal cord evoked by formalin. The decrease of c-fos or Som level due to intrathecal injection of ACTH in rats with chronic pain was prevented by injection of cyproheptadine, but not by bicuculline and naloxone. The results indicate that the serotonin receptor may be involved in ACTH induced analgesia.
Wu
Q
Q
Department of Physiology, Third Military Medical University, Chongqing 400038.
Li
X C
XC
Ruan
H Z
HZ
Li
H D
HD
D000324:Adrenocorticotropic Hormone / Q000494:pharmacology*; D000818:Animals; D003533:Cyproheptadine / Q000494:pharmacology; D005260:Female; D005557:Formaldehyde; D007150:Immunohistochemistry; D008297:Male; D009619:Nociceptors / Q000502:physiology; D010146:Pain / Q000139:chemically induced / Q000378:metabolism*; D010147:Pain Measurement; D017288:Pain Threshold; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis* / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D012702:Serotonin Antagonists / Q000494:pharmacology; D013004:Somatostatin / Q000096:biosynthesis* / Q000235:genetics; D013116:Spinal Cord / Q000378:metabolism*
D016760:Proto-Oncogene Proteins c-fos; D012702:Serotonin Antagonists; D005557:Formaldehyde; D003533:Cyproheptadine; D013004:Somatostatin; D000324:Adrenocorticotropic Hormone