Increased expression of spinal cord Fos protein induced by bladder stimulation after spinal cord injury.
These studies examined Fos protein expression in spinal cord neurons synaptically activated by stimulation of bladder afferent pathways after spinal cord injury (SCI). In urethan-anesthetized Wistar rats after SCI for 6 wk, intravesical saline distension significantly (P </= 0.005) increased the number of Fos-immunoreactive (IR) cells in the rostrolumbar (L1, 38 cells/section; L2, 29 cells/section) and caudal lumbosacral (L6, 140 cells/section; S1, 110 cells/section) spinal cord compared with control animals, but Fos expression in the L5 segment was not altered. The distribution of Fos-IR cells was also altered in the lumbosacral spinal cord. Significantly greater numbers of Fos-IR cells were distributed in the dorsal commissure and medial and lateral dorsal horn after intravesical distension in SCI animals. Large percentages of parasympathetic (75%) and sympathetic (85%) preganglionic neurons also expressed Fos-IR after intravesical distension in SCI animals. These results demonstrate that bladder distension produces increased numbers and an altered distribution pattern of Fos-IR cells after SCI. This pattern resembles that after noxious irritation of the bladder in control animals. Pretreatment with capsaicin significantly reduced the number of Fos-IR cells induced by bladder distension after SCI. These data suggest that SCI can reveal an altered Fos expression pattern in response to a nonnoxious bladder stimulus that is partially mediated by capsaicin-sensitive bladder afferents.
Vizzard
M A
MA
University of Vermont College of Medicine, Departments of Neurology and Anatomy and Neurobiology, Burlington, Vermont 05405, USA. mvizzard@zoo.uvm.edu
D019342:Acetic Acid / Q000008:administration & dosage; D000283:Administration, Intravesical; D000818:Animals; D001339:Autonomic Fibers, Preganglionic / Q000378:metabolism; D002211:Capsaicin / Q000008:administration & dosage; D002452:Cell Count / Q000187:drug effects; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D008161:Lumbosacral Region; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology; D009474:Neurons / Q000166:cytology / Q000201:enzymology; D009929:Organ Size / Q000502:physiology; D016760:Proto-Oncogene Proteins c-fos / Q000096:biosynthesis*; D051381:Rats; D017208:Rats, Wistar; D012965:Sodium Chloride / Q000008:administration & dosage; D013116:Spinal Cord / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D013119:Spinal Cord Injuries / Q000378:metabolism*; D001743:Urinary Bladder / Q000187:drug effects / Q000502:physiology*; D014551:Urinary Tract / Q000187:drug effects
D016760:Proto-Oncogene Proteins c-fos; D012965:Sodium Chloride; D002795:Choline O-Acetyltransferase; D019342:Acetic Acid; D002211:Capsaicin