Autonomic neuroscience : basic & clinical
-
Complex regional pain syndrome type I (CRPS I) is a frequent complication after injuries of the upper limbs. The pathophysiology of this disease remains unclear, although disturbances of the sympathetic nervous system have been detected in several clinical studies, and sympathetic blocks resolve the symptoms in many of the cases. To investigate the meaning of sympathetic dysfunction at the beginning of the disease, 27 patients with distal radial fracture were examined prospectively during the course of the disease with regard to their clinical symptoms and their peripheral sympathetic nervous function. ⋯ With regard to the unaffected contralateral hand, CRPS I patients also showed impaired sympathetic nervous function. The results of the present study suggest that the disturbances in the sympathetic nervous system in CRPS I patients are systemic and not limited to the affected limb. Their occurrence before the clinical breakout of the disease may serve as a marker that might be useful for early therapy and lead to further understanding of the pathophysiology of CRPS I.
-
The rat L5/6 facet joint is innervated from L1 to L5 dorsal root ganglions (DRGs) multisegmentally. Sensory fibers from L1 and L2 DRGs were reported to innervate nonsegmentally through the paravertebral sympathetic trunks, while those from L3 to L5 DRGs segmentally innervate the L5/6 facet joint. The presence of substance P (SP) and calcitonin gene-related peptide (CGRP) immunoreactive (ir) nerve fibers has been demonstrated in the lumber facet joints, but their ratios have not been determined. ⋯ Of the F-G labeled neurons, the ratios of SP-ir L1, L2, L3, L4 and L5 DRG neurons were 13, 15, 29, 31 and 30%, respectively, and those of CGRP-ir neurons were 17, 24, 44, 56 and 50%, respectively. The ratios of SP and CGRP-ir neurons in L1 and L2 DRGs were significantly less than those in L3, L4 or L5 DRGs. In conclusion, the neurons of L3, L4 and L5 DRGs may have a more significant role in pain sensation of the facets than L1 and L2 DRG neurons.
-
The results of neural tracing studies suggest that vagal afferent fibers in cervical and thoracic branches innervate the esophagus, lower airways, heart, aorta, and possibly the thymus, and via abdominal branches the entire gastrointestinal tract, liver, portal vein, billiary system, pancreas, but not the spleen. In addition, vagal afferents innervate numerous thoracic and abdominal paraganglia associated with the vagus nerves. Specific terminal structures such as flower basket terminals, intraganglionic laminar endings and intramuscular arrays have been identified in the various organs and organ compartments, suggesting functional specializations. ⋯ There is also good evidence for a role of vagal afferents in nociception, as manifested by affective-emotional responses such as increased blood pressure and tachycardia, typically associated with the perception of pain, and mediated via central reflex pathways involving the amygdala and other parts of the limbic system. The massive central projections are likely to be responsible for the antiepileptic properties of afferent vagal stimulation in humans. Furthermore, these functions are in line with a general defensive character ascribed to the vagal afferent, paraventricular system in lower vertebrates.