Tonic and Reflex Functions of Medullary Sympathetic Cardiovascular Centers

Alexander, Robert S.

doi:10.1152/jn.1946.9.3.205

Cited by 378 publications

(116 citation statements)

References 15 publications

Supporting

Mentioning

103

Contrasting

Unclassified

Order By: Relevance

“…2). A similar relationship has previously been described for pulse synchronous activity in cervical sympathetic nerves (Alexander, 1946). Also, the efferent sympathetic tract from the medulla to the spinal cord is mainly uncrossed (Chen, Lim, Wang & Yi, 1937;Harrison, Wang & Berry, 1939).…”

Section: Discussionsupporting

confidence: 72%

See 1 more Smart Citation

Centrally evoked sympathetic discharge: a functional study of medullary vasomotor areas

Kahn¹,

Mills²

1967

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The medulla oblongata was stimulated electrically in decerebrate cats following bilateral vagotomy. Changes in splanchnic nerve discharge evoked by stimulation of pressor and depressor areas in the medulla are correlated with changes in arterial pressure. An interaction of baroreceptor afferents with the efferent sympathetic system at the level of the medulla and/or spinal cord is demonstrated. Evidence is presented which suggests that it is possible to alter activity selectively in a given division (splanchnic) of the sympathetic outflow.2. Evoked responses were categorized as follows: (a) Sustained splanchnic activation; an immediate increase in total splanchnic activity occurred with only a small, gradual decline in activity during the stimulation period. Mild stimulation ,tA) raised systolic pressure by 60-80 mm Hg and stronger stimulation (300-400 ,uA) increased pressure by 100-150 mm Hg. When comparable pressor responses were elicited from points on either side of the mid line, splanchnic excitation was greater with homolateral stimulation (left side).(b) Unsustained splanchnic activation; an immediate increase in activity occurred which declined sharply as systolic pressure rose by 60-100 mm Hg during stimulation. Such a decline was attributed to the influence of baroreceptor afferents. Thus, if previous carotid occlusion was maintained during stimulation, the decline in activity was minimized although the pressor response increased. It is suggested that the structures yielding unsustained responses differ from those yielding sustained responses in their functional relation with the baroreceptor afferents.(c) Reduced splanchnic discharge during direct medullary stimulation;22-2 NORMAN KAHN AND ELLIOTT MILLS a partial or complete inhibition of splanchnic activity was obtained, which was sometimes accompanied by a 20-40 mm Hg reduction in systolic pressure. However, the direction and magnitude of the systemic pressure change were not as consistently related to the splanchnic response as they were during activation. Even if splanchnic efferent activity were elevated by carotid occlusion, stimulation still reduced discharge.

show abstract

Section: Discussionsupporting

confidence: 72%

“…Systematic exploration of the medulla and pons with stimulating electrodes (Wang & Ranson, 1939) and transection of the brain-stem at various levels (Alexander, 1946) have established the location of these vasomotor areas.…”

Section: Introductionmentioning

confidence: 99%

Centrally evoked sympathetic discharge: a functional study of medullary vasomotor areas

Kahn¹,

Mills²

1967

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…Regarding this phenomenon the studies of Alexander (3,4) and Fisher, Raule and Seraphin (8) on the cardiac sympathetic centers in the spinal cord are interesting; they found that the deafferenated cardioacceleratory centers were enable to discharge the spontaneous impulses. The question arises as to whether sympathetic impulses to the eye in the normal condition are attributed to only the autochthonous activity initiated from the cilio-spinal centers themselves or whether the upper brain is related to the origin of their activity.…”

Section: Fig 10 the Fiber Which Is Uninffluenced By Light Illuminatmentioning

confidence: 99%

The Activity of the Cilio-Spinal Centers and Their Inhibition in Pupillary Light Reflex

1960

View full text Add to dashboard Cite

“…The literature affords robust anatomical/ physiological evidence that compression of the ninth and tenth cranial nerve (CN IX-X) root entry/exit zone (REZ) and adjacent ventrolateral medulla-especially on the left side, known to convey inputs from the baroreceptors of the (left-sided) cardiac atrium-could be the origin of systemic arterial hypertension. 2,3,4,6,8,9,11,15,16,18,22,23,25,[42][43][44] In the quest for patients affected with essential hypertension to be candidates for vascular decompression, as many as 14 studies have been conducted to investigate the reliability of MRI for the detection of compressive vessels with a potential role in the genesis of hypertension. 1,10,12,21,24,28,35,37,39,45,50,57,58,61 In most of these publications, images of vascular contact/compression at the ventrolateral medulla were reported at a higher rate in patients with hypertension than in those with normal blood pressure (BP).…”

mentioning

confidence: 99%

Hypertension of neurogenic origin: effect of microvascular decompression of the CN IX-X root entry/exit zone and ventrolateral medulla on blood pressure in a prospective series of 48 patients with hemifacial spasm associated with essential hypertension

Sindou

Mahmoudi

Brînzeu

2015

JNS

View full text Add to dashboard Cite

aBBreViatiONS AICA = anterior inferior cerebellar artery; BA = basilar artery; BP = blood pressure; CN = cranial nerve; ENMG = electroneuromyographic; GP = general practitioner; HFS = hemifacial spasm; MVD = microvascular decompression; NVC = neurovascular compression; PICA = posterior inferior cerebellar artery; REZ = root entry/exit zone; VA = vertebral artery. SuBmitted August 1, 2014. accepted December 30, 2014. iNclude wheN citiNg Published online July 31, 2015; DOI: 10.3171/2014.12.JNS141775. diSclOSure The authors report no conflict of interest concerning the materials or methods used in this study or the findings specified in this paper. OBJect In spite of solid anatomical and physiological arguments and the promising results of Jannetta in the 1970s, treating essential hypertension by microvascular decompression (MVD) of the brainstem has not gained acceptance as a mainstream technique. The main reason has been a lack of established selection criteria. Because of this, the authors' attempts have been limited to patients referred for MVD for hemifacial spasm (HFS) who also had hypertension likely to be related to neurovascular compression (NVC). methOdS Of 201 patients referred for HFS, 48 (23.8%) had associated hypertension. All had high-resolution MR images that demonstrated NVC. All underwent MVD of the root exit/entry zone (REZ) of the ninth and tenth cranial nerves (CN IX-X) and adjacent ventrolateral medulla in addition to the CN VII REZ. Effects on hypertension, graded using the WHO classification, were studied up to the latest follow-up, which was 2-16 years from the time of surgery, 7 years on average. Also, effects of MVD on blood pressure (BP) according to the side of vascular compression were evaluated. reSultS Preoperatively, hypertension was severe in all but 1 of the patients; in spite of medical treatment, 47 patients still had WHO Grade 1 or 2 hypertension, and 18 still had unstable BP. After MVD, at latest follow-up, BP had returned to normal (i.e., systolic pressure < 140 mm Hg) in 28 patients; 14 of these patients (29.10% of the whole series) were able to maintain normal BP without any antihypertensive treatment; the other 14 still required some medication to maintain their BP below 140 mm Hg (p < 0.0001). Also, at latest follow-up, BP remained unstable in only 8 of the 18 patients with instability prior to MVD (p < 0.02). Analysis according to side of compression showed that of the 30 patients with left-sided compression, 17 had their BP normalized (without medication in 11 cases), and of the 18 patients with right-sided compression, 11 had their BP normalized (without medication in 3 cases). The difference between sides was not significant. cONcluSiONS These results argue for considering MVD for the treatment of hypertension likely to be due to NVC at the CN IX-X REZ and adjacent ventrolateral medulla. Criteria for selecting patients with hypertension alone still need to be established and could include the following indications: apparently essential hypertension, likely to be neuro...

show abstract

Tonic and Reflex Functions of Medullary Sympathetic Cardiovascular Centers

Cited by 378 publications

References 15 publications

Centrally evoked sympathetic discharge: a functional study of medullary vasomotor areas

Centrally evoked sympathetic discharge: a functional study of medullary vasomotor areas

The Activity of the Cilio-Spinal Centers and Their Inhibition in Pupillary Light Reflex

Hypertension of neurogenic origin: effect of microvascular decompression of the CN IX-X root entry/exit zone and ventrolateral medulla on blood pressure in a prospective series of 48 patients with hemifacial spasm associated with essential hypertension

Contact Info

Product

Resources

About