MORPHOLOGICAL STUDIES OF THE NOCICEPTIVE DISORDER IN THE INHERITED HYDROCEPHALIC RAT (HTX AND Hyd)

Abstract

Inherited hydrocephalic rat develops irritability and/or pareses during progression of hydrocephalus in associated with hemorrhages in dorsal root ganglia and spinal cord which transmit the sensory information. The strains of inherited hydrocephalic rats, HTX and Hyd, were employed to investigate sensory disorder, especially nociception due to a cut incision or formalin injection to the foot pad of left hindlimb. The rats were perfused after three hours and Fos-like immunoreactivities were examined (FLI) in the neurons of dorsal horn in spinal lumbar cord (L4).
1) FLI positive cells were seen more expressive in the hydrocephalic rats without or with hemor-rhage in dorsal root ganglia than in the normal appearing rats. The hydrocephalic rats with spinal pericanal hemorrhage and ganglia hemorrhage showed less FLI positive cells than normal appearing rats.
2) FLI positive cells were moderately expressed in the deeper lamina in the hydrocephalic rats.
3) Dead neurons were scattered in the thalamic ventral posterior nuclei and medial geniculate bodies in the hydrocephalic rat.
These results suggested that inherited hydrocephalic rats are hyperalgesic and FLI is morphologically a useful tool expressed by sensory disorder.