Ultrastructural Changes in the Cerebral Artery Wall Induced by Long-Term Sympathetic Denervation

-This study investigates the role of cervical sympathectomy in the prevention of acute vasospasm induced by meningeal haemorrhage in rabbits. Sixteen adult English Norfolk rabbits were divided into 2 experimental groups: bilateral cervical sympathectomy of the superior sympathetic ganglion (SSSG, n=8), and bilateral SSSG and sympathectomy of the inferior sympathetic ganglion (SISG, n=8). Other 24 animals were used as controls. Basilar artery diameter was evaluated by angiography. SSSG protected the animals against developing cerebral vasospasm; SSSG associated with SISG did not increase this effect.KEY WORDS: subarachnoid haemorrhage, vasospasm, cervical sympathectomy .Efeitos da simpatectomia cervical sobre o vasoespasmo induzido por hemorragia meníngea em coelhos RESUMO -Este estudo investiga o papel da simpatectomia cervical na prevenção do vasoespasmo agudo induzido por hemorragia meníngea em coelhos. Para tanto, foram utilizados 16 coelhos adultos da raça N o rfolk inglesa, divididos em 2 grupos experimentais: simpatectomia cervical bilateral do gânglio simpáti-co cervical superior (SSSG, n=8) e SSSG associada a simpatectomia cervical bilateral do gânglio simpático c e rvical inferior (SISG, n=8). Outros 24 animais foram usados como controles. Os diâmetros das art é r i a s basilares foram avaliados por medições após angiografias. SSSG protegeu os animais contra o vasoespasmo; SSSG associada a SISG não aumentou este efeito.

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“…Animals with induced subarachnoid haemorrh age presented vasospasm (G2). Similar results have been reported 14,[16][17][18][19][20][21][22] .…”

Section: Discussionsupporting

confidence: 91%

Effects of cervical sympathectomy on vasospasm induced by meningeal haemorrhage in rabbits

Faleiros

Maffei

Resende

2006

Arq. Neuro-Psiquiatr.

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“…It may also be produced, on a more chronic basis, by growth of less distensible connective tissue for which sympathetic influences are a trophic factor. 11,12 The participation of the sympathetic nervous system in the alterations of arterial distensibility in a post-transplantation organ does not exclude the involvement of other factors, given the complex alterations in the local milieu brought about by organ transplantation, although our data allow us to exclude or consider unlikely a number of them. After 40 days, the transplanted hand still showed some edema, which subsided entirely over the subsequent follow-up period.…”

Section: Giannattasio Et Almentioning

confidence: 76%

Arterial Stiffening Influence of Sympathetic Nerve Activity

et al. 2005

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Abstract-Studies in animals and humans suggest that sympathetic activity exerts a stiffening influence on large and middle-sized artery walls. We sought to obtain further evidence on this issue by measuring radial artery distensibility in an allotransplanted and thus denervated hand using the contralateral artery as control. In 2 men, blood pressure was measured by a semiautomatic device (Dinamap). Diastolic diameter, systo-diastolic diameter excursion (ultrasound Wall Track system), and distensibility (Reneman formula) of both radial arteries were measured at a level corresponding to 4 cm below the suture of the transplanted hand 40 days after surgery and every 4 weeks for the next 6 months. After surgery, systo-diastolic diameter excursion and distensibility were much greater in the transplanted radial artery than in the contralateral vessel, reaching values similar to the contralateral ones after 4 months, when signs of reinnervation of the transplanted hands had appeared. Radial deinnervation was accompanied by an increased arterial distensibility, which provides further evidence of the sympathetic stiffening effect on arterial wall in humans. Key Words: denervation Ⅲ sympathetic nervous system Ⅲ transplantation S ympathetic nerve activity exerts a "tonic" stiffening influence on arterial wall. 1,2 This has been shown in animals in which chemical sympathectomy was accompanied by an increase in carotid artery distensibility. 3 It has also been shown in humans in whom anesthesia of the brachial plexus and anesthesia of the low spinal cord and lumbar sympathectomy were all followed by an increase in the distensibility of the radial or the femoral artery, reflecting the stiffening effect neural influences exerted on the vessel wall. 4 Our hospital started a program of allotransplantation of the hand 2 years ago. This gave us a chance to determine what happens to arterial distensibility in transplanted organs and to make use of another human "model" on which to study the relationship between sympathetic tone and arterial distensibility, which could be measured at various times after the surgical intervention in the radial artery below the transplantation line, using the values obtained from the contralateral vessel as control. This article reports the results obtained in 2 patients. MethodsWe studied 2 men (patient 1, age 35 years; patient 2, age 31 years) who underwent allotransplantation of the right hand, which had been lost in a previous car accident. Both patients underwent a routine pretransplantation investigation and morphological and functional testing of the forearm stumps to ensure immunologic and mechanical donor-recipient compatibility. They were administered treatment with monoclonal antibodies anti-CD25 (Baxilimab, Simulect), FK506 (tacrolimus, Prograf), mycophenolate mofetil (Cell Cept), and prednisone immediately after surgery to prevent graft rejection. Maintenance therapy was unchanged throughout the study duration. The post -treatment program of rehabilitation (started as the swelling subsided...

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“…The effects of the sympathetic nervous system on VSM differentiation have not been studied extensively, but there is evidence to suggest that sympathetic neurons (SNs) promote or maintain VSM differentiation. Dimitriadou et al (10) observed that sympathetic denervation produced morphological changes in VSM and suggested that these changes were characteristic of VSM dedifferentiation. Kacem et al (19) found that VSMs in denervated arteries expressed more vimentin than corresponding innervated arteries.…”

mentioning

confidence: 99%

Sympathetic innervation promotes vascular smooth muscle differentiation

Damon¹

2005

American Journal of Physiology-Heart and Circulatory Physiology

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The sympathetic nervous system (SNS) is an important modulator of vascular smooth muscle (VSM) growth and function. Several lines of evidence suggest that the SNS also promotes VSM differentiation. The present study tests this hypothesis. Expression of smooth muscle myosin (SM2) and ␣-actin were assessed by Western analysis as indexes of VSM differentiation. SM2 expression (normalized to ␣-actin) in adult innervated rat femoral and tail arteries was 479 Ϯ 115% of that in noninnervated carotid arteries. Expression of ␣-actin (normalized to GAPDH or total protein) in 30-dayinnervated rat femoral arteries was greater than in corresponding noninnervated femoral arteries from guanethidine-sympathectomized rats. SM2 expression (normalized to ␣-actin) in neonatal femoral arteries grown in vitro for 7 days in the presence of sympathetic ganglia was greater than SM2 expression in corresponding arteries grown in the absence of sympathetic ganglia. In VSM-endothelial cell cultures grown in the presence of dissociated sympathetic neurons, ␣-actin (normalized to GAPDH) was 300 Ϯ 66% of that in corresponding cultures grown in the absence of neurons. This effect was inhibited by an antibody that neutralized the activity of transforming growth factor-␤2. All of these data indicate that sympathetic innervation increased VSM contractile protein expression and thereby suggest that the SNS promotes and/or maintains VSM differentiation. endothelial cells; transforming growth factor-␤; ␣-actin; myosin VASCULAR SMOOTH MUSCLE (VSM) differentiation is critical for the normal development of blood vessels. VSMs must differentiate from the synthetic phenotype required for growth of blood vessels to the contractile phenotype required for appropriate regulation of blood pressure and blood flow. VSM differentiation is associated with increased expression of contractile proteins such as smooth muscle actin and myosin (12,14,15,17,20,21,24,28). In many cardiovascular diseases including hypertension, atherosclerosis, and ischemic heart disease, differentiated contractile VSM dedifferentiates to a more synthetic phenotype (1,13,20,23,28). This "developmental regression" can compromise cardiovascular function. The physiological and pathological mechanisms that modulate the differentiation of VSM are not well understood.The sympathetic nervous system is an important determinant of vascular growth and function (5,6,8,27,33). The effects of the sympathetic nervous system on VSM differentiation have not been studied extensively, but there is evidence to suggest that sympathetic neurons (SNs) promote or maintain VSM differentiation. Dimitriadou et al. (10) observed that sympathetic denervation produced morphological changes in VSM and suggested that these changes were characteristic of VSM dedifferentiation. Kacem et al. (19) found that VSMs in denervated arteries expressed more vimentin than corresponding innervated arteries. These authors suggested that vimentin was a marker for dedifferentiated VSM. The mechanisms of these effects were not investi...

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Ultrastructural Changes in the Cerebral Artery Wall Induced by Long-Term Sympathetic Denervation

Cited by 38 publications

References 28 publications

Effects of cervical sympathectomy on vasospasm induced by meningeal haemorrhage in rabbits

Effects of cervical sympathectomy on vasospasm induced by meningeal haemorrhage in rabbits

Arterial Stiffening Influence of Sympathetic Nerve Activity

Sympathetic innervation promotes vascular smooth muscle differentiation

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