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PubMed1977

Preoperative selection of patients for lumbar sympathectomy by use of the Doppler index.

Yao and Bergan [8] have shown that an ankle systolic index of more than 0.25 is associated with a high rate of success from lumbar sympathectomy. This association has been borne out in our small series. We have also suggested that diseases that obviously compromise collateral circulation might be a relative contraindication to sympathectomy. Although incomplete, literature on collateral flow in relation to sympathectomy tends to confirm this idea. Consideration of such diseases as a contraindication to sympathectomy might further increase the success rate after sympathectomy. Regardless, ankle systolic index alone appears to be a reliable objective, non-invasive method of selecting patients with an increased chance of success from lumbar sympathectomy.

Adult↗
PubMed1990

Long-term chemical sympathectomy leads to an increase of neuropeptide Y immunoreactivity in cerebrovascular nerves and iris of the developing rat.

Short-term (surgical) and long-term (chemical) sympathectomy have revealed the presence of a population of neuropeptide Y-like immunoreactive nerve fibres which do not degenerate in parallel with noradrenaline-containing nerves supplying cerebral vessels and the iris of the rat. Two days after bilateral removal of the superior and middle cervical ganglia of 7-week-old rats, noradrenaline-containing nerves could not be detected along any of the arteries of the rat circle of Willis or of the iris, but 18-32% of neuropeptide Y-like immunoreactive nerves remained. Long-term treatment (6 weeks) with guanethidine commencing in developing 1-week-old rats caused degeneration of the sympathetic neurons in cervical ganglia and disappearance of 5-hydroxydopamine-labelled nerves (that showed dense-cored vesicles at the electron microscope level) from rat cerebral vessels, but did not significantly change the density of neuropeptide Y-like immunoreactive axons on the vessels. Furthermore, whilst in control rats neuropeptide Y-like immunoreactivity was localized largely within 5-hydroxydopamine-labelled cerebrovascular nerves, after long-term sympathectomy with guanethidine, neuropeptide Y-like immunoreactivity was seen only in nerves lacking small dense-cored vesicles. A small number of catecholamine-containing nerves appeared along the internal carotid and anterior cerebral arteries after long-term sympathectomy; these may arise from neurons of central origin. These results suggest that as a consequence of long-term sympathectomy with guanethidine, compensatory changes occur, involving an increase in the expression of neuropeptide Y-like immunoreactivity in non-sympathetic axons in cerebrovascular nerves and iris of the rat. In contrast, the neuropeptide Y-like immunoreactive nerves in the dura mater appear to be entirely sympathetic, since none were present after short-term sympathectomy and none appeared after long-term sympathectomy.

Adrenergic Fibers↗
PubMed1991

Neurogenic and non-neurogenic inflammation in the rat paw following chemical sympathectomy.

Rats with chemical sympathectomy, induced either at neonatal age (long-term sympathectomy) or in adult animals (short-term sympathectomy) by guanethidine or by 6-hydroxydopamine, were used to determine the contribution of sympathetic noradrenergic fibres to afferent neuron-mediated responses and to non-neurogenic inflammation in the rat. Following long-term sympathectomy with 6-hydroxydopamine there was a 66% depletion of noradrenaline in the paw skin. This was accompanied by a 20-53% increase in the levels of sensory neuropeptides in the paw skin and sciatic nerve. A hypersensitivity towards heat stimuli was observed in the tail immersion test. Neither neurogenic plasma protein extravasation following antidromic nerve stimulation or upon local mustard oil application nor the development of the non-neurogenic carrageenan oedema and its susceptibility towards indomethacin were impaired. Neonatal guanethidine sympathectomy caused an 86% depletion of noradrenaline in the paw skin and neurogenic plasma protein extravasation upon antidromic nerve stimulation was impaired. Sensory neuropeptides were unchanged in the skin after neonatal guanethidine and only calcitonin gene-related peptide content was increased in the spinal cord and sciatic nerves. The other observations (i.e. the sensitivity towards heat stimuli, the neurogenic mustard oil inflammation and the non-neurogenic carrageenan oedema) were similar to those observed after neonatal 6-hydroxydopamine treatment. Following the short-term treatment protocol of 6-hydroxydopamine, an 82% depletion of noradrenaline in the skin was accompanied by an increase in calcitonin gene-related peptide content, whereas after adult guanethidine (60% depletion of noradrenaline) levels of sensory neuropeptides were unchanged. Neurogenic plasma protein extravasation was found to be unimpaired after either type of short-term chemical sympathectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Afferent Pathways↗
PubMed1995

Plasticity in the myenteric plexus of the rat ileum after long-term sympathectomy.

To investigate the effect of chronic sympathectomy on the innervation of a tissue with an extensive intrinsic component, 1-week-old rat pups were treated with 50 mg/kg guanethidine for 3 weeks, a treatment shown to produce complete and long-lasting sympathectomy, and the ileum examined. Changes in the levels of noradrenaline, neuropeptide Y, calcitonin gene-related peptide, substance P and vasoactive intestinal polypeptide in the external muscle layers containing the myenteric plexus of the ileum were determined between 6 and 20 weeks of age. After sympathectomy, noradrenaline levels were initially depleted (3% of age-matched controls at 6 weeks, P < 0.001, and 18% of age-matched controls at 12 weeks, P < 0.001), but were not significantly reduced at 20 weeks (67% of age-matched controls). Such increases in noradrenaline content with time after sympathectomy did not occur in the mesenteric vein (levels in 20-week-old sympathectomized rats were 2% of the control values (P < 0.001). In the myenteric plexus, catecholamine fluorescent nerve fibers were seen in the 12-week-old sympathectomized rats, although tyrosine hydroxylase-immunoreactivity was absent. Guanethidine sympathectomy had no effect on the neuropeptide levels in 6-week-old rat ileum but there was a selective increase at 20 weeks; the levels of calcitonin gene-related peptide and substance P were increased (X3, P < 0.001 and X1.6, P < 0.05, respectively) while vasoactive intestinal polypeptide and neuropeptide Y levels were unchanged. Short-term sympathectomy (destruction of sympathetic nerve terminals by acute 6-hydroxydopamine treatment) had no affect on noradrenaline or peptide levels in this tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenergic Fibers↗
PubMed2005

Clinical experience in 397 consecutive thoracoscopic sympathectomies.

BACKGROUND: The purpose of this study is to evaluate the safety and efficacy of thoracoscopic sympathectomy for the treatment of hyperhidrosis, blushing, reflex sympathetic dystrophy, and digital ischemia. METHODS: We conducted a retrospective review of 202 patients who underwent thoracoscopic sympathectomy at the University of Maryland from March 1992 to April 2003. RESULTS: Three hundred ninety-seven procedures were performed on 202 patients (105 women, 97 men). Mean age was 29 years (range, 9 to 65). Indications for surgery included hyperhidrosis, facial blushing, digital ischemia, and reflex sympathetic dystrophy. Synchronous bilateral sympathectomies were performed in 194 patients; right side alone (n = 6); left side alone (n = 1); 1 patient had staged bilateral sympathectomies. Single incision with lung isolation technique was used. There was no mortality. Preoperative symptoms resolved completely or significantly improved in greater than 90% of patients. One patient with reflex sympathetic dystrophy recurred and 1 patient with hyperhidrosis complained of significant compensatory sweating. Compensatory sweating to a lesser degree occurred in approximately one third of patients. Complications included asymptomatic pleural effusion (n = 1), pneumothorax (n = 1), and reoperation for chylothorax that was identified early (n = 1). In 2 patients treated for facial blushing, Horner's syndrome developed postoperatively; 1 of them subsequently underwent blepharoplasty. In 3 patients, hyperesthesias developed at the incision. CONCLUSIONS: Thoracoscopic sympathectomy can be performed safely and with excellent results. Compensatory sweating is the main side effect, although significant complaints from this are rare. Horner's syndrome remains an extremely uncommon complication as a result of thoracoscopic sympathectomy at our institution.

Adolescent↗
PubMed2006

Endoscopic thoracic sympathectomy for severe hyperhidrosis: impact of restrictive denervation on compensatory sweating.

BACKGROUND: Compensatory sweating is noted frequently after sympathectomy and may be difficult to control in some patients. This prospective trial was projected to measure the impact of limited denervation on compensatory sweating while performing endoscopic thoracic sympathectomy. METHODS: One hundred seventy-eight patients (127 female and 51 male) with severe primary hyperhidrosis unsuccessfully treated by conservative means entered the study. Group A was treated with sympathectomy from T2 to T4. In group B sympathectomy was performed from T3 to T5. Physical condition was measured after 1, 6, and 24 months by means of the SF-36 Health Survey Test. RESULTS: Evaluation rate was 94.9%. Horner's syndrome was not detected, recurrence rate was 0.6%, and rate of persistent pneumothorax was 2.3%. Compensatory sweating was reported with 17.1% in group A and diminished to 4.9% in group B. Gustatory sweating was comparable in both groups (4.3% versus 4.9%). Satisfaction rate was 97% in patients with palmar hyperhidrosis, 95% for axillary hyperhidrosis, and 87% for facial hyperhidrosis. Discomfort originating from compensatory sweating was less than symptoms from primary hyperhidrosis 24 months after endoscopic thoracic sympathectomy in more than 90%. Only 7.1% of the entire group was not satisfied. CONCLUSIONS: Our study demonstrates that limiting denervation beyond T2 ganglion offers good clinical results in axillary as well as palmar hyperhidrosis and may reduce the risk for compensatory sweating. In women, reduction was as high as 75% and in men, near 50%. Our impression is that severe compensatory sweating and the majority of stellate ganglion lesions occur as a result of starting sympathectomy at level T2.

Adult↗
PubMed2006

Effect of sympathectomy and demedullation on increased myenteric and dorsal vagal complex Fos-like immunoreactivity by cholecystokinin-8.

Chemical sympathectomy with daily, intraperitoneal (IP) injections of guanethidine sulfate to adult rats, attenuated myenteric, but not dorsal vagal complex (DVC) Fos-like immunoreactivity (Fos-LI) by cholecystokinin-8 (CCK). This technique destroys only 60-70% of the sympathetic neurons, and spares the hormonal source of catecholamines, the adrenal medulla. The goal of the current study is to evaluate the effect of complete sympathectomy or destroying 100% of the sympathetic neurons by injecting guanethidine to 1-day-old pups (40 mg/kg daily for 5 weeks), and surgically removing the adrenal medulla. In the DVC, demedullation and sympathectomy-demedullation increased Fos-LI by CCK in the area postrema and nucleus of the solitary tract, but sympathectomy-demedullation increased it only in the area postrema. In the myenteric plexus, sympathectomy increased this response in the duodenum, and demedullation increased it in the duodenum and jejunum. On the other hand, sympathectomy-demedullation attenuated myenteric Fos-LI in the jejunum. These results indicate that catecholamines may play an inhibitory role on the activation of the DVC neurons by CCK. In the myenteric neurons, however, catecholamines may have both inhibitory and excitatory roles depending on the level of the intestine e.g., duodenum vs. jejunum. This may also indicate that CCK activates the enteric neurons by different mechanisms or through different pathways.

Adrenal Medulla↗
PubMed2000

Needlescopic thoracic sympathectomy: treatment for palmar hyperhidrosis.

BACKGROUND: Open thoracic sympathectomy has been the established option for patients with essential hyperhidrosis. Recently, video-assisted endoscopic sympathectomy has provided a simple, safe, reliable, and cost-effective alternative to the earlier technique. With advances in instrumentation, performing the procedure through 2-mm and 3-mm needlescopic ports is now possible. The authors evaluate the effectiveness of so-called needlescopic thoracic sympathectomy for the treatment of primary hyperhidrosis. METHODS: Thirty five consecutive patients with a mean age of 24 years, including 23 men and 12 women, underwent bilateral needlescopic thoracic sympathectomies at the National University Hospital of Singapore. RESULTS: The mean operative duration was 56 minutes, and the mean hospital stay was 1.2 days. In no patient did Horner's syndrome or significant pneumothorax develop. The rate of success, defined as completely dry hands, was 97%. Two patients had unilateral recurrences that responded well to repeat needlescopic sympathectomies. We performed a total of 72 sympathectomies. CONCLUSIONS: Our study demonstrates that the use of miniature port access sites produces excellent medical and cosmetic results and is associated with a short hospital stay and low risk of complications.

Adult↗
PubMed1998

Parasympathetic varicosity proliferation and synaptogenesis in rat eyelid smooth muscle after sympathectomy.

Parasympathetic innervation to eyelid smooth muscle inhibits sympathetic neurotransmission pre-junctionally without appreciable direct post-junctional effects. However, 5 weeks after sympathectomy, parasympathetic stimulation elicits substantial cholinergically mediated contractions. This study examined ultrastructural changes accompanying the conversion to parasympathetic excitation. In intact muscles, 64+/-9 nerve varicosities were encountered per 104 micron2. Most were close to muscle cells and not fully enclosed by supporting cells. Axo-axonal synapses were observed occasionally. Two days following sympathectomy, varicosity numbers were reduced by 97% and, relative to controls, remaining varicosities were farther from muscle cells and more frequently fully enclosed by supporting cells, but contained greater numbers of small spherical and large dense vesicles. By 6 weeks post-sympathectomy, numbers of varicosities per unit muscle volume increased to 14% of controls. These varicosities differed from those at 2 days in being closer to smooth muscle cells, less frequently enclosed, and having fewer small vesicles. These findings indicate that intact eyelid smooth muscle varicosities are predominantly sympathetic, but a small number of parasympathetic varicosities are present, some of which may form pre-junctional synapses with sympathetic nerves. Between 2 days and 6 weeks post-sympathectomy, varicosities increased in number and established appositions with smooth muscle cells. This suggests that parasympathetic nerves are capable of re-innervating an atypical smooth muscle target after sympathectomy, and that parasympathetic synaptogenesis is likely to contribute to conversion from pre-junctional inhibition to post-junctional excitation after sympathectomy.

Animals↗
PubMed1998

Sympathetic skin response and patient satisfaction on long-term follow-up after thoracoscopic sympathectomy for hyperhidrosis.

OBJECTIVES: To determine effect of sympathectomy for hyperhidrosis on sympathetic skin response (SSR) during long-term follow-up. Patient satisfaction was assessed and surgical complications noted. DESIGN: Prospective, Open, Non-randomised study. MATERIALS AND METHODS: Patients who had undergone bilateral thoracoscopic sympathectomy for hyperhidrosis underwent postoperative assessment of SSRs. A 15 mA stimulus was applied over the median nerve contralateral to the sympathectomy and evoked electrodermal activity was recorded from the sympathectomised palm using a Dantec Counterpoint Mk 2. Patient satisfaction with surgery was assessed by questionnaire and visual analogue score (0-1.0). RESULTS: Of 26 patients, 21 were female. Mean (range) age was 23 (9-36) years. Mean (range) follow up was 39 (4-138) months. 12% of cases had residual or recurrent symptoms. Median (range) patient satisfaction was 0.83 (0.06-1.0). In 7/52 palms recurrent SSRs were not detected. Repeated measures analysis of variance found amplitude of SSR to be of low significance with respect to time since surgery (F = 0.48; p = 0.49) and incidence of compensatory sweating (F = 2.38; p = 0.14). CONCLUSION: Thoracoscopic sympathectomy for hyperhidrosis is an effective procedure. Following sympathectomy SSRs are not permanently abolished, but return of SSRs does not correspond with symptom recurrence. As such, SSRs are a poor tool for objective assessment of long-term outcome following sympathectomy.

Adolescent↗
PubMedDate not supplied

Cutaneous innervation in man before and after lumbar sympathectomy: evidence for interruption of both sensory and vasomotor nerve fibres.

BACKGROUND: Rest pain and severe ischaemia in patients who are unable to be offered (further) surgery to revascularize the lower limb is still problematic. Lumbar sympathectomy has been used for many years but the mechanisms by which this works are not absolutely clear. Both sensory and vasomotor fibres travel in the lumbar sympathetic chain and the effects of lumbar sympathectomy on these nerve types have been investigated in the present paper. METHODS: Immunohistochemical methods were used to detect neuropeptides contained in sensory and vasomotor nerves in the lower limb skin of (i) patients having amputations for peripheral vascular disease (PVD) after previous (chemical or surgical) sympathectomy; (ii) patients having amputations for PVD without previous (chemical or surgical) sympathectomy; and in control normal skin. The three groups are compared and the results are discussed. RESULTS: Normal and PVD controls had intact sensory and vasomotor nerves around dermal cutaneous blood vessels, but these were completely or virtually completely lost after lumbar sympathectomy, by either chemical or surgical means. CONCLUSIONS: Lumbar sympathectomy severs both vasomotor and sensory fibres, suggesting that relief of rest pain may be explained not only by increased cutaneous and muscle blood flow, but also by nociceptive sensory denervation.

Aged↗
PubMed2001

The effects of chemical sympathectomy on testicular injury in varicocele.

OBJECTIVE: To determine whether the sympathetic nervous system plays a role in the contralateral testicular deterioration encountered in varicocele. MATERIALS AND METHODS: Forty male Sprague-Dawley albino rats (28 days old) were divided equally into four treatment groups, i.e. (1) sham operation, (2) with varicocele, (3) treated by chemical sympathectomy plus varicocele, and (4) chemical sympathectomy only. Chemical sympathectomy was induced by administering intraperitoneal 6-OH dopamine (100 microg/g for 5 days) in groups 3 and 4; groups 1 and 2 received equal volumes of physiological saline by the same route. All rats underwent laparotomy and part of the left renal vein (distal to the spermatic vein confluence) was isolated and encircled with a 4/0 silk suture. The suture was left untied in group 2, and tied around a 24 F peripheral venous cannula in groups 3 and 4. The testes were then excised when the rats were 70 days old; malondialdehyde (MDA) in the testicular tissue was assayed by the thiobarbituric acid-reactive substances method, and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels were determined by spectrophotometric analysis. RESULTS: Varicocele resulted in a significant increase in MDA levels in both testes and chemical sympathectomy prevented this effect. SOD and GSH-Px values were significantly decreased in both testes in group 2; chemical sympathectomy also prevented this effect. CONCLUSION: An induced unilateral varicocele significantly increases the biochemical indicators of tissue hypoxia in both testes. As this increase was prevented by chemical sympathectomy, the sympathetic nervous system may play a role in the testicular degeneration associated with varicocele.

Animals↗
PubMed2002

Plasma catecholamines in Buerger's disease: effects of cigarette smoking and surgical sympathectomy.

OBJECTIVES: to study the influence of tobacco exposure and sympathectomy on basal sympathoadrenal function of patients with Buerger's disease. DESIGN: plasma catecholamines were measured before and after smoking, in patients with Buerger's disease (n=13), in patients with Buerger's disease submitted to surgical bilateral lumbar sympathectomy (n=13), and in healthy volunteers (n=16). MATERIALS AND METHODS: venous blood samples were collected before and 2h after smoking one cigarette (0.9mg nicotine). Plasma concentrations (pg/ml) of dihydroxiphenylalanine (pL-DOPA), noradrenalin (pNA), adrenalin (pAD) and 3,4-dihydroxiphenylacetic acid (pDOPAC) were determined. RESULTS: Buerger's patients have low basal plasma catecholamines compared to volunteers: pNA (501 (196-927) vs 1858 (968-3663)) and pAD (71 (31-109) vs 193 (116-334)). Sympathectomy increased pL-DOPA, pAD and pDOPAC, but not pNA. After smoking, pNA only decreased in volunteers (1858 (968-3663) vs 1064 (535-2393)). In Buerger+sympathectomy group, smoking lowered pAD (700 (58-3379) vs 278 (54-429)). CONCLUSIONS: in Buerger's disease there is an impairment of sympathoadrenal function with an altered peripheral adrenergic response to cigarette smoking. Patients submitted to sympathectomy have high pAD, but this benefit is reversed after smoking. This might be clinically relevant given the association between cigarette smoking and the manifestations of Buerger's disease and the controversy on the effectiveness of sympathectomy in the management of the disease.

Adrenal Glands↗
PubMed2001

Thoracoscopic sympathectomy for palmar hyperhidrosis: effects on pulmonary function.

Palmar hyperhidrosis, probably caused by an over-reactivity of sympathetic nerves passing through the second and the third thoracic sympathetic ganglia (T2 & T3 ganglia), can only be cured by sympathectomy. Such sympathetic denervation may also alter pulmonary function. Previous studies have shown that open sympathectomy can cause significant deterioration in pulmonary function, however, the surgical procedure itself may contribute to the change. Recently thoracoscopic sympathectomy has been developed as a minimally invasive but effective treatment for palmar hyperhidrosis. In order to investigate the effect of sympathectomy, pulmonary function was compared before and four weeks after operation in 20 patients. Forced vital capacity (FVC) (-2.3%), forced expiratory volume in one second (FEV1) (-6.1%), and FEV1/FVC (-4.6%) were all slightly but significantly decreased four weeks after thoracoscopic sympathectomy. Also the instantaneous forced expiratory flow at 75%, 50% and 25% of the FVC (Vmax25, Vmax50, Vmax75) in flow-volume curves were decreased (-1.6%, -8.4%, and -20% respectively). Therefore, thoracoscopic sympathectomy minimises pulmonary restrictive effects but allows subclinical small airway obstructive effects to become more evident.

Adolescent↗
PubMed1998

Thoracoscopic upper thoracic sympathectomy for primary palmar hyperhidrosis--the combined paediatric, adolescents and adult experience.

OBJECTIVE: To present our experience, over the past 4 years, of thoracoscopic upper thoracic sympathectomy in patients with primary palmar hyperhidrosis. DESIGN: Retrospective study. SETTING: University hospital, Israel. SUBJECTS: 402 thoracoscopic upper thoracic sympathectomies in 223 patients over a period of 4 years. INTERVENTIONS: Thoracoscopic ablation of ganglia and severing of the sympathetic chain at the level of T2 and T3. 142 patients underwent bilateral simultaneous sympathectomy, 37 had bilateral non-simultaneous sympathectomy and 44 had unilateral sympathectomy. RESULTS: 220 patients (98.7%) had an uneventful postoperative course and were discharged the following day. Three patients with residual pneumothorax required intercostal drainage and were discharged on the third postoperative day. 219 patients (98.2%) were completely satisfied, having immediate and permanent relief of palmar sweating. Four patients were dissatisfied. CONCLUSION: The thoracoscopic approach to the upper thoracic sympathectomy is at present the procedure of choice. Early operation for severe palmar hyperhidrosis is indicated to save a child many years of frustration and discomfort.

Adolescent↗
PubMed2001

Effect of chemical sympathectomy with 6-hydroxydopamine on osteoclast activity in the gerbilline middle ear bulla.

HYPOTHESIS: Chemical sympathectomy with 6-hydroxydopamine (HDA) increases middle ear bulla bone resorption in the Mongolian gerbil. BACKGROUND: Many diseases of the middle ear have pathologic processes linked to abnormal bone remodeling. Numerous factors controlling bone remodeling have been identified. An understanding of these factors and their role in pathologic remodeling is therefore essential. Sympathectomy, induced both surgically and pharmaceutically, is known to increase middle ear bone resorption, suggesting a role for the central nervous system in bone metabolism. This effect, however, may be confounded by hemodynamic changes induced by hemicranial surgical sympathectomy or by uncertainty in the action of pharmaceutical agents on the sympathetic nervous system. In this experiment, a third modality with unique properties, chemical sympathectomy with HDA, was used to quantify further the effect of sympathectomy on middle ear bone remodeling. METHODS: Eight gerbils designated experimental received intraperitoneal injections of HDA (75 mg/kg) for 1 week, whereas eight animals designated control received similar injections of saline. One week after injections, the animals were euthanized and bulla bone samples were analyzed histomorphometrically to determine osteoclastic activity. In addition, to assess for any direct effects on bone metabolism, the activity of HDA was determined in vitro using the calvarial calcium release assay. RESULTS: The in vitro study found HDA to have no direct stimulatory activity on calcium release. The in vivo study showed HDA to increase osteoclastic activity significantly in middle ear bone. CONCLUSION: HDA-induced sympathectomy increases bone resorption in gerbilline middle ear bone.

Animals↗
PubMed1987

Respiration in awake cats: sympathectomy and deafferentation of carotid bifurcations.

Respiratory effects of sympathectomy of the carotid bifurcations and, in a subsequent experiment, bilateral carotid sinus nerve section were examined in six awake resting cats. In each intact and denervated state, sequential breaths were analyzed at 10-min intervals up to 80 min. Individual breath frequency (f), tidal volume (VT), and ventilation (V = f X VT) were determined. In individual cats, sympathectomy or deafferentation could cause significant increases or decreases in ventilation or no change. Thus the range of spontaneous variability in breath V as well as minute ventilation (VE), averaged for the group, were not consistently altered in the same direction by either sympathectomy or deafferentation of the carotid bifurcations. Interestingly, in most cats after both sympathectomy (5 of 6) and deafferentation (4 of 6), VT increased and f decreased relative to V. Despite this, after sinus nerve section in two cats arterial PO2 decreased and arterial PCO2 tended to increase relative to VE, suggesting possible effects of deafferentation on ventilation-perfusion balance. Sympathectomy also affected timing such that inspiratory time began to exceed 0.5 of the breath duration at a lower breath f; this effect of sympathectomy was reversed to intact values by subsequent sinus deafferentation. Thus, in eupneic awake cats, sympathetics normally suppress reflex modulation of central timing from carotid chemoreceptors and/or baroreceptors.

Afferent Pathways↗
PubMed2000

Sympathectomy, which induces membranous bone remodeling, has no effect on endochondral long bone remodeling in vivo.

Sympathectomy has been shown to induce resorption within the membranous middle ear bone of gerbils. It is unknown whether sympathectomy exerts a similar effect on endochondral long bone. In the present study, guanethidine sulfate (GS) and 6-hydroxydopamine (HDA) were administered to gerbils to induce sympathectomy. One week later, samples of middle ear bulla bone and radial long bone were harvested and assessed for osteoclastic activity. Histomorphometric analysis showed both pharmacologic sympathectomy with GS and chemical sympathectomy with HDA significantly increased the osteoclast counts and osteoclast surfaces of bulla bone samples but not radial long bone samples, respectively. In contrast, HDA but not GS increased the osteoclast profile area of both long bone and membranous bone samples when compared with vehicle-treated controls. Sympathectomy, induced both chemically and pharmacologically, thus has been shown to increase resorption in membranous bone but not endochondral long bone in the gerbilline model.

Animals↗