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Pentobarbital microinjected into a restricted locus in the upper brainstem induces a general anesthesia-like state characterized by atonia, loss of consciousness, and pain suppression as assessed by loss of nocifensive response to noxious stimuli. This locus is the mesopontine tegmental anesthesia area (MPTA). Although anesthetic agents directly influence(More)
OBJECT Recent progress in the understanding of abnormal electrical behavior in injured sensory neurons motivated an examination, at the ultrastructural level, of trigeminal roots of patients with trigeminal neuralgia (TN). METHODS In 12 patients biopsy specimens of trigeminal root were obtained during surgery for microvascular decompression. Pathological(More)
This study was aimed at measuring the kinetics of retrograde death among primary sensory neurons axotomized by transection of the ipsilateral sciatic nerve in adult rats. Using electrophysiological and retrograde transport methods, we first determined that most sciatic afferents enter the spinal cord along the L4 and L5 dorsal roots (DRs), and that about(More)
Tyrosine hydroxylase immunocytochemistry was used to reveal the sympathetic postganglionic axons that sprout to form basket-like skeins around the somata of some primary sensory neurons in dorsal root ganglia (DRGs) following sciatic nerve injury. Ultrastructural observations in rats revealed that these sprouts grow on the surface of glial lamellae that(More)
La Forte et al. (this issue) failed to find an increase in the numbers of dorsal root ganglion (DRG) neurons in rats of advancing age. However, their conclusion that our data (Devor and Govrin-Lippmann, 1985) to this effect were methodologically flawed is based on an incorrect application of our counting method. In fact, both their counting method and ours(More)
Nerve injury frequently triggers hyperexcitability and the ectopic initiation of impulses in primary afferent axons. An important consequence is neuropathic paresthesias and pain. Electrogenesis in normal afferents depends on appropriate Na+ channel concentrations. Therefore, we have asked whether injury might trigger changes in axolemmal Na+ channel(More)
Some injured sensory fibers ending in an experimental neuroma in the rat sciatic nerve discharge spontaneously. Furthermore, many become sensitive to a range of physical and chemical stimuli. The resulting afferent barrage is thought to contribute to paresthesias and pain associated with peripheral nerve injury. We report that the development of such(More)
Afferent fibers ending in nerve end neuromas in rats generate a substantial ectopic discharge and are sensitive to light pressure and to circulating adrenaline. Treatment of the nerve with colchicine or vinblastine at the time of the nerve section resulted in a dose-dependent reduction in the extent of this discharge. Such treatment also reduced neuroma(More)