Preserved autoregulation in the rhesus spinal cord after high cervical cord section

Kobrine, Arthur I.; Doyle, Thomas F.; Newby, N; Rizzoli, Hugo V.

doi:10.3171/jns.1976.44.4.0425

Cited by 28 publications

(7 citation statements)

References 9 publications

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“…The treated animals were given an infusion of lidocaine via the right femoral vein starting 15 cording to the following schedule: 1.5 mg/kg over the initial 3 minutes, 3 mg/kg over the next 30 minutes, and 1 mg/kg every 30 minutes for the remainder of the experiment. We have found that this method of lidocaine administration in cats maintains lidocaine blood levels of 3 to 4 tzg/ml.…”

Section: Methodsmentioning

confidence: 99%

Effect of intravenous lidocaine on experimental spinal cord injury

Kobrine¹,

Evans²,

LeGrys³

et al. 1984

Journal of Neurosurgery

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A series of experiments was conducted to study the effect of systemic intravenous administration of lidocaine on neurological recovery after acute experimental spinal cord injury in cats. The spinal cord was injured by the rapid inflation of an epidural balloon at T-6. The physiological integrity of the spinal cord ceased within 2 seconds in all animals, as demonstrated by acute disappearance of the somatosensory evoked response (SER). There was essentially no return of the SER in the five untreated animals when monitored for 4 hours post-injury. All of the pathological specimens from these animals revealed severe central cord hemorrhage. Intravenous lidocaine was begun 15 minutes after the injury in five animals. Three of these animals had significant return of the SER. The pathological specimens from the lidocaine-treated animals revealed either mild or moderate central cord hemorrhage. The results of this experiment suggest that systemic lidocaine administration has a significant beneficial effect in the treatment of acute spinal cord injury.

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Section: Methodsmentioning

confidence: 99%

Effect of intravenous lidocaine on experimental spinal cord injury

Kobrine¹,

Evans²,

LeGrys³

et al. 1984

Journal of Neurosurgery

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“…The autoregulatory response of spinal cord white matter is preserved after severing the cord high in the neck, suggesting a local regulatory mechanism. 39 Autoregulation of cerebral blood flow has been demonstrated to be altered in a variety of circumstances. In chronic hypertension, cerebral blood flow autoregulation is adapted to higher pressures with a shift of the entire autoregulatory curve to the right.…”

Section: Table 2 Cerebral Blood Flow In the Ratmentioning

confidence: 99%

Autoregulation of spinal cord blood flow: is the cord a microcosm of the brain?

Hickey¹,

Albin²,

Bunegin³

et al. 1986

Stroke

142

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SUMMARY The autoregulatory capability of regional areas of the brain and spinal cord was demonstrated in 18 rats anesthetized with a continuous infusion of intravenous pentothal. Blood flow was measured by the injection of radioactive microspheres (Co 57 , Sn 113 , Ru 103 , Sc 4 *). Blood flow measurements were made at varying levels of mean arterial pressure (MAP) which was altered by neosynephrine to raise MAP or trimethaphan to lower MAP. Autoregulation of the spinal cord mirrored that of the brain, with an autoregulatory range of 60 to 120 mm Hg for both tissues. Within this range, cerebral blood flow (CBF) was 59.2 ± 3.2 ml/100 g/min (SEM) and spinal cord blood flow (SCBF) was 61.1 ± 3.6. There was no significant difference in CBF and SCBF in the autoregulatory range. Autoregulation was also demonstrated regionally in the left cortex, right cortex, brainstem, thalamus, cerebellum, hippocampus and cervical, thoracic and lumbar cord. This data provides a coherent reference point hi establishing autoregulatory curves under barbiturate anesthesia. Further investigation of the effects of other anesthetic agents on autoregulation of the spinal cord is needed. It is possible that intraspinal cord compliance, like intracranial compliance, might be adversely affected by the effects of anesthetics on autoregulation. Stroke Vol 17, No 6, 1986 HEMODYNAMIC AUTOREGULATION, a mechanism intrinsic to the cerebrovascular system, and also present in many other tissues, maintains tissue blood flow within a narrow range despite changes in perfusion pressure. It has been firmly established as the primary blood flow regulatory mechanism in the brain and constitutes a physiological adjustment that is of major importance in maintenance of a homeostatic internal environment of the brain. The first observation of cerebral autoregulation was made by Fog in 1934. 1 -2 He observed the responses of pial vessels of cats through a cranial window under conditions of varying arterial blood pressure and noted dilation with a fall in blood pressure and constriction with a rise in blood pressure. Lassen, in his review in 1959, established the concept of cerebral autoregulation based on actual measurements of blood flow during blood pressure alterations. 3 Since that time, cerebral autoregulation has been extensively investigated and it has been found that under normotensive conditions mean arterial blood pressure can be varied from a lower limit of 60 mm Hg to an upper limit of 130 mm Hg without any measurable change in blood flow.4 Below these limits, cerebral blood flow markedly falls, and above these limits, forced dilation of arterioles occurs which is associated with disruption of the blood brain barrier and edema formation. Received July 17, 1985; revision #1 accepted January 29, 1986. vascular dynamics. However, a comparison between the autoregulatory capabilities of these two tissues has not been demonstrated. The purpose of this study was to simultaneously measure spinal cord and cerebral blood flow under conditions of varying...

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“…The possibility of a long-tract craniospinal control system was discredited when Kobrine et al (1976a) found that a high cervical cord section in the Rhesus did not affect the intraspinal autoregulation, but the suspicion that extraspinal components of the autonomic nervous system may be at least partially implicated in SCBF control has received some experimental support. Young et al (1982) showed that the SCBF in cats increased along with elevations of the systemic pressure after paravertebral sympathectomy, whereas Iwai and Monafa (1992) claimed that lower lumbar sympathectomy in rats produced only a moderate effect on the regional SCBF.…”

Section: Discussionmentioning

confidence: 99%

Arteriovenous glomeruli of the human spinal cord and their possible functional implications

Parke

2004

Clinical Anatomy

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A previous investigation of the radiculomedullary vascular distribution of the human spinal cord showed an immediate filling of the peripheral spinal veins during arterial injections. Because the perfused medium, a mixture of latex and India ink, had a sufficient viscosity to preclude capillary passage, an extensive system of arteriovenous anastomoses (AVA) was indicated. The injection of five additional anatomic cadaver spinal cords was undertaken to specifically determine the intraparenchymal position and structure of these AVA. It was found that only cleared and transilluminated longitudinal parasagittal sections adequately showed that the AVA were formed by an extensive array of intricately coiled arteriovenous glomeruli (AVG) that could pass substantial amounts of blood from third order arterial branches to equivalently sized veins, bypassing the capillary bed. The epithelioid structure of these AVG channel walls, coupled with their highly innervated adventitial tissue indicated a possible functional relationship to similar structures found in the ends (digital pads) of mammalian extremities. Stained serial sections of injected cords showed the vascular relations with nerve fibers derived from the intraspinal parenchyma as well as a possible extraparenchymal autonomic fiber source. The numbers and extent of these AVG complexes suggested they might be involved in the remarkable autoregulation of spinal cord blood flow (SCBF) that is impervious to middle range changes in systemic blood pressure. Future research may more accurately determine the functional role of these previously unreported human spinal AVG, particularly in their possible relation to SCBF autoregulation in normal and injured spines.

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Preserved autoregulation in the rhesus spinal cord after high cervical cord section

Cited by 28 publications

References 9 publications

Effect of intravenous lidocaine on experimental spinal cord injury

Effect of intravenous lidocaine on experimental spinal cord injury

Autoregulation of spinal cord blood flow: is the cord a microcosm of the brain?

Arteriovenous glomeruli of the human spinal cord and their possible functional implications

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