Effects of adrenocorticotropic hormone and electroacupuncture on formalin-induced NOS-positiTe neurons in the spinal cord of rats

摘要

AIM:To study the effects of adrenocorticotropic hormone(ACTH) and electroacupuncture (EA) on formalin-induced nitric oxide synthetase (NOS)-positive neurons increases in the spinal cord or rats.METHODS:ACTH was administered by intrathecal injection (i.t.)and EA stimulation on “jiaji” point was performed by 1 mA 50Hz,5mA 5Hz and 1mA 5Hz respectively.The NOS-positive neurons were assayed by NADPH-diaphorase histochemistry.RESULTS:The results showed that both ACTH(0.5u,i.t.)and EA stimulation (1mA 50Hz,5mA 5Hz,1mA 5Hz) on “jiaji” point 30min significantly reduced the formalin-induced NOS-ositive neurons in the rat dorsal horn.The combinative use of ACTH (0.5u,i.t.) and EA(1mA 5Hz) caused a more marked reduction of the numbers of NOS positive neurons than that of the single ACTH or EA.Those effects were partially reversed by pretreatment with either the substrate of NOS,L-arginine (10nmol,i.t.)or opioid antagonist naloxone(10g,i.t.).CONCLUSION:These results suggests that both ACTH and EA might inhibit the formalin-induced NOS-positive neurons increases and have a synergic effect acting via a different pathway.