Journal of the autonomic nervous system
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J. Auton. Nerv. Syst. · Dec 1997
The second thoracic sympathetic ganglion determines palm skin temperature in patients with essential palmar hyperhidrosis.
Sympathectomy of the second (T2) and third (T3) thoracic ganglion is frequently performed for essential palmar hyperhidrosis and occasionally performed, in addition to stellectomy, for idiopathic Raynaud's disease. The increased palm skin temperature after the operation probably results from increased skin perfusion. To determine whether it was possible to limit the extent of sympathectomy for these patients, we recorded palm skin temperature after electric stimulation of stellate, T2 and T3 ganglia, and after randomized electrocautery of T2 and T3 ganglia in 20 patients. ⋯ While rising significantly after destruction of T2 ganglion in the presence of intact T3 ganglion (P = 0.00001), palm skin temperature did not rise significantly after T3 destruction in the presence of intact T2 (P = 0.779). Following T2 and T3 destruction, however, palm skin temperature rose despite stellate stimulation. This suggests that T2 ganglion determines palm skin temperature while stellate and other upper thoracic ganglia may play a minor role, that T2 sympathectomy suffices for the treatment of essential palmar hyperhidrosis, and that sympathectomy for Raynaud's disease might skip stellectomy.
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J. Auton. Nerv. Syst. · Jun 1997
Temperature dependency of the vagal chronotropic response in the young puppy: an 'environmental-autonomic interaction'.
We investigated the effects of mild hypothermia (34.3 +/- 0.2 degrees C [mean +/- SD]), hyperthermia (40.8 +/- 0.2 degrees C) and hypoxia (PaO2 = 43 +/- 4 mmHg) on the response to heart rate to continuous right vagus nerve stimulation (the 'vagal chronotropic response') in young puppies, aged 5-22 days. Puppies were anesthetized with alpha-chloralose, vagotomized and pre-treated with propranolol (1 mg/kg i.v.) and phentolamine (1 mg/kg, 1-2 mg/kg/h i.v.). Hypoxia (n = 9) did not significantly alter the resting sinus cycle length and did not alter the response of sinus cycle to a 30 s train of 8 Hz right vagal stimulation. ⋯ In contrast to hypothermia, mild hyperthermia (n = 8) decreased the resting sinus cycle length slightly (-5 +/- 5% change) and significantly attenuated the cardiac vagal chronotropic response (from 88 +/- 28% change in sinus cycle length (normothermia) to 50 +/- 26% (hyperthermia)). These changes were also reversible with the re-establishment of normothermia. This demonstrates that clinically relevant, environmentally-induced changes in body temperature can directly and reversibly modify parasympathetic efferent responses.
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J. Auton. Nerv. Syst. · Mar 1997
Skin blood flow abnormalities in a rat model of neuropathic pain: result of decreased sympathetic vasoconstrictor outflow?
Loose ligation of a sciatic nerve in rats provokes signs and symptoms like those observed in human conditions of neuropathic pain. Some of these have been associated with sympathetic dysfunction. Since the skin microcirculation in the rat is strongly influenced by sympathetic tone, abnormalities in skin blood flow may be used as an indirect measure of sympathetic dysfunction. ⋯ As compared to the values obtained before ligation (= 100%): (1) the vasoconstrictor response was impaired (65%, P < 0.01) from day 1 onwards, whereas (2) basal skin blood flow was increased (171%; P < 0.01) from day 3 until day 5, and decreased (51%, P < 0.0001) from day 7 until day 28. At day 28, blockade of impulse propagation in the loosely ligated sciatic nerve (by means of lidocaine) did not increase the lowered level of skin blood flow. These findings suggest that in the chronic construction injury model loose ligation of a sciatic nerve reduces sympathetic vasoconstrictor outflow, which, in turn may induce supersensitivity of skin microvessels to catecholamines.
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J. Auton. Nerv. Syst. · Nov 1996
Significance of sympathetic skin response in the assessment of autonomic failure in patients with spinal cord injury.
As a result of spinal cord injury (SCI) descending spinal sympathetic pathways can be severed. Because of its clinical significance, the aim of this study was to assess the disturbance of the spinal sympathetic pathway by clinical and electrophysiological examinations. The sympathetic skin response (SSR) due to electrical stimulation of median nerve and transcranial magnetic stimulation was examined in 70 patients with complete and incomplete spinal cord injury. ⋯ There was no patient with preserved SSR potentials who developed symptoms of autonomic dysreflexia (AD). However, all patients with episodes of AD showed abolished SSR at the hands and feet even in incomplete SCI patients. The results of the SSR recordings in SCI patients fit with the assumption that the development of AD is related to the disconnection of the spinal sympathetic centers from supraspinal control.
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J. Auton. Nerv. Syst. · Dec 1995
Variation in the anatomy of the lumbar sympathetic chain in the rat.
The rat is often used when the sympathetic nervous system contribution to various physiological and pathological processes is studied. These experiments require a detailed knowledge of the lumbar sympathetic chain anatomy since the macroscopic anatomy of the L2 and L3 levels of the sympathetic chain, which innervate a major portion of the hindleg, is highly variable. We have performed a detailed study of the anatomy of the lumbar sympathetic chain in 245 Sprague-Dawley rats. Through anatomical characterization of the L2 and L3 sympathetic ganglia white and gray ramus communicants, our study provides an anatomical guide for studies of the function of the lumbar sympathetic chain in the rat.