Role of the sinu-vertebral nerve in low back pain and anatomical basis of therapeutic implications

Low back pain is frequent and results in major disability for patients. This anatomical study was done to understand mechanisms involved in that pain. Two kinds of innervation are present in the lumbar spine: one depends on the somatic nervous system and the other on the sympathetic nervous system. The sympathetic nerves are the sinu-vertebral nerves and the rami communicantes which innervate the intervertebral disc, the ventral surface of the dura mater, the longitudinal dorsal ligament and the longitudinal ventral ligament. The sinu-vertebral nerve was described first by Luschka in 1850. This nerve is implicated in diffuse low back pain because of its pathway and its sympathetic component. This nerve cannot directly reach a somatic element at each level of the lumbar spine, so must first reach the L2 spinal ganglion. Thus, there is a "hole" in the somatic innervation between L3 and L5 because the dorsal nerves do not reach the skin at these levels. The pain therefore takes another route through the sympathetic system. Discogenic pain is mediated by the sinu-vertebral nerves, and through the rami communicantes reaches the L2 spinal ganglion. Anatomical and clinical features reinforce this hypothesis.

Expression of bcl-2, bax and bcl-xl in human gliomas: a re-appraisal

We have analyzed the expression of the anti-apoptotic proteins bcl-2, bcl-xl and that of bax, a pro-apoptotic protein, in human WHO grade II astrocytomas (LGA) and WHO grade IV glioblastoma multiforme (GBM). Tumors were obtained immediately after surgical resection and were analyzed by immunohistochemistry (IHC), laser confocal microscopy (LCM) and immunoblots. Both IHC and immunoblot analysis indicated that the expression of bcl-xl was not significantly different between LGA and GBM. IHC indicated that the expression of bcl-2 was inversely correlated to the grade of the tumors (i.e more cells were bcl-2 positive in LGA than in GBM) while the expression of bax was unaffected by the grade of the tumor. In contrast, immunoblots revealed a parallel increase in the expression of bcl-2 and bax from the low to high grade tumor, suggesting a co-regulation of the expression of these two proteins during tumoral progression. Confocal analyses provide us with another possible level of complexicity in the regulation of apoptosis in these tumors, as these markers exhibited different subcellular localizations: bcl-2 was strictly associated with mitochondria and bcl-xl was present in both cytosolic and mitochondrial compartments while bax was found essentially in the cytosol of the tumoral cells. Taken together, our data suggest that the role of bcl-2 related proteins could be regulated at different levels in human astrocytomas (expression, subcellular localization, antigen exposure ...) which should be studied by different techniques.