Autonomic dysreflexia in a mouse model of spinal cord injury
Section snippets
Spinal cord transection
All protocols for these experiments were approved by the University of Western Ontario Animal Care Committee in accordance with the policies established in the Guide to Care and Use of Experimental Animals prepared by the Canadian Council on Animal Care. Thirteen 129Sv mice (The Jackson Laboratory) weighing between 20 and 30 g were divided into two groups: spinal cord-transected (n=7) and sham-injured (n=6). Anesthesia was induced using 4% halothane and maintained with 1–1.5% halothane in
Presence of autonomic dysreflexia
Two weeks after surgery the spinal cord-transected group was again anaesthetized by halothane. A cannula was implanted in the carotid artery and blood pressure measurements were taken. The average baseline blood pressure was at 80±10 mm Hg and mean blood pressure responses to stimulation were as follows: moderate cutaneous pinch caudal to the injury (35±6 mm Hg), tail pinch (25±7 mm Hg), and a 0.3-ml balloon distension of the colon (37±4 mm Hg) (Fig. 1). As expected, no escape response was
Discussion
To make use of the available spontaneous and engineered mouse mutants in the study of autonomic dysreflexia, we sought to characterize this disorder in wild-type mice. As different mouse strains may respond differently to neurotrauma (Steward et al., 1999), the choice of mouse strain was particularly important. We elected to use 129Sv mice because the majority of engineered mouse mutations have been generated on this genetic background (Simpson et al., 1997). Though graded models of spinal cord
Acknowledgements
This work was supported by the Ontario Neurotrauma Foundation Grant # ONAO 99124. Dr. Arthur Brown is a Research Scholar of the Heart and Stroke Foundation of Canada. Dr. Lynne Weaver was a Career Investigator of the Heart and Stroke Foundation of Canada. We would like to thank Kelly Galloway-Kay for assistance with histological sectioning and Jamie Bruce for assistance with the digital image analysis.
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2020, Experimental NeurologyCitation Excerpt :Considerable less attention has focussed on the possible participation of interneurones in deleterious gains of motor function (both somatic and autonomic) following SCI such as the development of spasticity (Bellardita et al., 2017) and autonomic dysreflexia (Hou et al., 2008). There is considerable evidence for an expansion of primary afferent projections to the spinal cord that correlate with the development of autonomic dysreflexia following spinal cord injury (Jacob et al., 2001; Krenz and Weaver, 1998; Weaver et al., 2001). Primary afferents do not project directly to sympathetic preganglionic neurones (SPNs), so local interneurons will be the target of these afferent projections.
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2012, Progress in NeurobiologyCitation Excerpt :In our experience, with SCI at a relatively low spinal level, we found no cases of severe autonomic dysreflexia. However, this complication can appear as a consequence of urinary retention, infection or even a change of position, as has been described by some authors (Jacob et al., 2001; Hagen et al., 2011). In the presence of this complication, the animal's head must be raised using pillows, and the noxious stimulus must be removed (usually bladder distention).
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2012, Experimental NeurologyCitation Excerpt :In this condition, the key changes occur below the site of injury. Collateral sprouting of CGRP-immunoreactive small diameter primary afferent fibers into the laminae III–V of the dorsal horn after SCI has been linked with the development of chronic neuropathic pain and autonomic dysreflexia (Christensen and Hulsebosch, 1997a, 1997b; Jacob et al., 2001; Krenz and Weaver, 1998; Krenz et al., 1999; Weaver et al., in press; Wong et al., 2000) (Fig. 1A). Sprouting of larger diameter fibers has also been noted after SCI (Krenz and Weaver, 1998) and may contribute to dysreflexia as this condition can also be induced by non-noxious stimuli such as light touch (Marsh and Weaver, 2004).
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