Participation of 5-hydroxytryptamine in pain-related behavior induced by nucleus pulposus applied on the nerve root in rats. Export

@article{citeulike:4133253, abstract = {STUDY DESIGN: The role of 5-hydroxytryptamine (5-HT) in sciatica in lumbar disc herniation (LDH) in rats was investigated. OBJECTIVE: We evaluated the effects of exogenous 5-HT applied on the nerve root on pain-related behavior, the release of endogenous 5-HT in plasma, and the expression of 5-HT2A receptors in dorsal root ganglion (DRG) in a rat LDH model. SUMMARY OF BACKGROUND DATA: In previous studies, 5-HT2A receptor antagonists improved sciatica in patients with LDH and attenuated pain-related behavior induced by nucleus pulposus applied to the nerve root in rats. METHODS: Adult female Sprague-Dawley rats were divided into four experimental groups [control group; low-dose (10 microg) 5-HT-group; high-dose (30 microg) 5-HT-group; and autologous nucleus pulposus (NP) and saline group] and each drug was applied to the L5 nerve root. Von Frey tests were used for pain-behavior testing. To assess levels of endogenous 5-HT released in capillaries surrounding inflamed nerve roots, we measured 5-hydroxyindole acetic acid (5-HIAA), a metabolite of 5-HT. Expression of 5-HT2A receptors in the left L5 DRG was examined by immunohistochemical and immunoblotting analyses in the control and NP groups. RESULTS: Mechanical withdrawal thresholds of the high-dose 5-HT and the NP groups were significantly decreased after surgery compared with the control group and recovered after 14 days in the high-dose 5-HT group. 5-HIAA in plasma was increased by nucleus pulposus applied on the nerve root for 7 days after surgery. The expression of 5-HT2A receptors was enhanced in a time-dependent manner by nucleus pulposus. CONCLUSION: Exogenous 5-HT to the nerve root induced pain-related behavior with short-lasting effects compared with the nucleus pulposus application. 5-HIAA content in plasma and expression of 5-HT2A receptors in DRG neurons increased early time points after the nucleus pulposus application. These results suggest that 5-HT plays a role in the early phase of the chemical pathogenesis of sciatica in LDH in rats.}, author = {Kato, K. and Kikuchi, S. and Konno, S. and Sekiguchi, M.}, citeulike-article-id = {4133253}, citeulike-linkout-0 = {http://dx.doi.org/10.1097/BRS.0b013e318173298b}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/18496345}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=18496345}, doi = {10.1097/BRS.0b013e318173298b}, issn = {1528-1159}, journal = {Spine}, keywords = {degeneration, disc, inflammation, pain}, month = {May}, number = {12}, pages = {1330--1336}, posted-at = {2009-03-04 22:28:10}, priority = {2}, title = {Participation of 5-hydroxytryptamine in pain-related behavior induced by nucleus pulposus applied on the nerve root in rats.}, url = {http://dx.doi.org/10.1097/BRS.0b013e318173298b}, volume = {33}, year = {2008} }

TY - JOUR ID - citeulike:4133253 L3 - citeulike-article-id:4133253 N2 - STUDY DESIGN: The role of 5-hydroxytryptamine (5-HT) in sciatica in lumbar disc herniation (LDH) in rats was investigated. OBJECTIVE: We evaluated the effects of exogenous 5-HT applied on the nerve root on pain-related behavior, the release of endogenous 5-HT in plasma, and the expression of 5-HT2A receptors in dorsal root ganglion (DRG) in a rat LDH model. SUMMARY OF BACKGROUND DATA: In previous studies, 5-HT2A receptor antagonists improved sciatica in patients with LDH and attenuated pain-related behavior induced by nucleus pulposus applied to the nerve root in rats. METHODS: Adult female Sprague-Dawley rats were divided into four experimental groups [control group; low-dose (10 microg) 5-HT-group; high-dose (30 microg) 5-HT-group; and autologous nucleus pulposus (NP) and saline group] and each drug was applied to the L5 nerve root. Von Frey tests were used for pain-behavior testing. To assess levels of endogenous 5-HT released in capillaries surrounding inflamed nerve roots, we measured 5-hydroxyindole acetic acid (5-HIAA), a metabolite of 5-HT. Expression of 5-HT2A receptors in the left L5 DRG was examined by immunohistochemical and immunoblotting analyses in the control and NP groups. RESULTS: Mechanical withdrawal thresholds of the high-dose 5-HT and the NP groups were significantly decreased after surgery compared with the control group and recovered after 14 days in the high-dose 5-HT group. 5-HIAA in plasma was increased by nucleus pulposus applied on the nerve root for 7 days after surgery. The expression of 5-HT2A receptors was enhanced in a time-dependent manner by nucleus pulposus. CONCLUSION: Exogenous 5-HT to the nerve root induced pain-related behavior with short-lasting effects compared with the nucleus pulposus application. 5-HIAA content in plasma and expression of 5-HT2A receptors in DRG neurons increased early time points after the nucleus pulposus application. These results suggest that 5-HT plays a role in the early phase of the chemical pathogenesis of sciatica in LDH in rats. IS - 12 JF - Spine SN - 1528-1159 EP - 1336 TI - Participation of 5-hydroxytryptamine in pain-related behavior induced by nucleus pulposus applied on the nerve root in rats. VL - 33 SP - 1330 KW - degeneration KW - disc KW - inflammation KW - pain AU - Kato, K AU - Kikuchi, S AU - Konno, S AU - Sekiguchi, M PY - 2008/05/20/ UR - http://dx.doi.org/10.1097/BRS.0b013e318173298b ER -