Effects of zopiclone and benzodiazepines on spinal reflexes, anemic decerebrate rigidity and benzodiazepine binding.

Abstract Decerebrate rigidity (DR) in humans results from a midbrain lesion and is manifested by an exaggerated extensor posture of all extremities. It is characterized by shortening and lengthening reactions and can be modified by tonic neck, labyrinthine (Magnus-de Kleijn), and phasic spinal reflexes. These criteria, and not extensor posture alone, reflect the observations of Sherrington and should form the basis of the clinical examination; however, the experimental-anatomical lesion and physiological findings can never be reproduced exactly in humans. “Tonic and cerebellar fits” are not the equivalent of DR, but are forms of muscle spasm that result in an extensor attitude. They are caused by irritation and excitation of the brain stem. The most common cause of DR in humans is trauma. The incidence of DR in head-injured patients may be as high as 40%, resulting in an average mortality rate of 80%; the presence of an extensor posture increases the mortality from 20 to 70%. The surgical removal of an intracranial lesion does not improve the high mortality rate in patients with craniocerebral trauma who are decerebrate. Although the Glasgow coma scale (GCS) does not consider the specific type of central nervous system abnormality caused by trauma, it is an accurate and accepted assessment of outcome after coma lasting longer than 6 hours. DR is a factor in the best motor response of the GCS and should be assigned major importance in the prognosis of comatose head-injured patients.

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Effects of l-threo-dihydroxyphenylserine on spinal reflexes and decerebrate rigidity in rats

General Pharmacology The Vascular System ◽

10.1016/0306-3623(88)90030-4 ◽

1988 ◽

Vol 19 (3) ◽

pp. 369-372

Author(s):

Hideki Ono ◽

Mitsuo Tanabe ◽

Takeshi Nakamura ◽

Nobuo Nagano ◽

Hideomi Fukuda

Keyword(s):

Spinal Reflexes ◽

Decerebrate Rigidity

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Multiple subluxations and comminuted fracture of the cervical spine in a sheep

Tierärztliche Praxis Ausgabe G Großtiere / Nutztiere ◽

10.15653/tpg-140371 ◽

2015 ◽

Vol 43 (01) ◽

pp. 44-38

Author(s):

C.-C. Lin ◽

K.-S. Chen ◽

Y.-L. Lin ◽

J. P.-W. Chan

Keyword(s):

Cervical Spine ◽

Pain Perception ◽

Cervical Vertebrae ◽

Traumatic Injury ◽

Spinal Reflexes ◽

Spine Trauma ◽

Blunt Force Trauma ◽

Comminuted Fracture ◽

History Of ◽

The Right

SummaryA 5-month-old, 13.5 kg, female Corriedale sheep was referred to the Veterinary Medicine Teaching Hospital, with a history of traumatic injury of the cervical spine followed by non-ambulatoric tetraparesis that occurred 2 weeks before being admitted to the hospital. At admission, malalignment of the cervical spine with the cranial part of the neck deviating to the right was noted. Neurological examinations identified the absence of postural reactions in both forelimbs, mildly decreased spinal reflexes, and normal reaction to pain perception tests. Radiography revealed malalignment of the cervical vertebrae with subluxations at C1–C2 and C2–C3, and a comminuted fracture of the caudal aspect of C2. The sheep was euthanized due to a presumed poor prognosis. Necropsy and histopathological findings confirmed injuries of the cervical spine from C1 to C3, which were consistent with the clinical finding of tetraparesis in this case. This paper presents a rare case of multiple subluxations of the cervical spine caused by blunt force trauma in a young sheep. These results highlight the importance of an astute clinical diagnosis for such an acute cervical spine trauma and the need for prompt surgical correction for similar cases in the future.

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Changes in Crossed Spinal Reflexes After Peripheral Nerve Injury and Repair

Journal of Neurophysiology ◽

10.1152/jn.00305.2001 ◽

2002 ◽

Vol 87 (4) ◽

pp. 1763-1771 ◽

Cited By ~ 34

Author(s):

Antoni Valero-Cabré ◽

Xavier Navarro

Keyword(s):

Sciatic Nerve ◽

Action Potential ◽

Peripheral Nerve ◽

Nerve Injury ◽

Peripheral Nerve Injury ◽

Tibialis Anterior ◽

Tibial Nerve ◽

Spinal Reflexes ◽

Injury And Repair

We investigated the changes induced in crossed extensor reflex responses after peripheral nerve injury and repair in the rat. Adults rats were submitted to non repaired sciatic nerve crush (CRH, n = 9), section repaired by either aligned epineurial suture (CS, n = 11) or silicone tube (SIL4, n = 13), and 8 mm resection repaired by tubulization (SIL8, n = 12). To assess reinnervation, the sciatic nerve was stimulated proximal to the injury site, and the evoked compound muscle action potential (M and H waves) from tibialis anterior and plantar muscles and nerve action potential (CNAP) from the tibial nerve and the 4th digital nerve were recorded at monthly intervals for 3 mo postoperation. Nociceptive reinnervation to the hindpaw was also assessed by plantar algesimetry. Crossed extensor reflexes were evoked by stimulation of the tibial nerve at the ankle and recorded from the contralateral tibialis anterior muscle. Reinnervation of the hindpaw increased progressively with time during the 3 mo after lesion. The degree of muscle and sensory target reinnervation was dependent on the severity of the injury and the nerve gap created. The crossed extensor reflex consisted of three bursts of activity (C1, C2, and C3) of gradually longer latency, lower amplitude, and higher threshold in control rats. During follow-up after sciatic nerve injury, all animals in the operated groups showed recovery of components C1 and C2 and of the reflex H wave, whereas component C3 was detected in a significantly lower proportion of animals in groups with tube repair. The maximal amplitude of components C1 and C2 recovered to values higher than preoperative values, reaching final levels between 150 and 245% at the end of the follow-up in groups CRH, CS, and SIL4. When reflex amplitude was normalized by the CNAP amplitude of the regenerated tibial nerve, components C1 (300–400%) and C2 (150–350%) showed highly increased responses, while C3 was similar to baseline levels. In conclusion, reflexes mediated by myelinated sensory afferents showed, after nerve injuries, a higher degree of facilitation than those mediated by unmyelinated fibers. These changes tended to decline toward baseline values with progressive reinnervation but still remained significant 3 mo after injury.

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Supraspinal inhibition of a cutaneous vascular reflex in the cat

American Journal of Physiology-Legacy Content ◽

10.1152/ajplegacy.1964.207.2.303 ◽

1964 ◽

Vol 207 (2) ◽

pp. 303-307 ◽

Cited By ~ 8

Author(s):

B. J. Prout ◽

J. H. Coote ◽

C. B. B. Downman

Keyword(s):

Carotid Sinus ◽

Spinal Reflexes ◽

Descending Pathways ◽

Skin Response ◽

Reflex Arc ◽

Vascular Reflex ◽

Carotid Sinus Nerve Stimulation ◽

Sympathetic Discharge ◽

Stimulation Of ◽

Cerebellar Stimulation

In cats anesthetized with chloralose-urethane mixture, stimulation of an afferent nerve evoked a vasoconstrictor reflex (VCR) and a galvanic skin response (GSR) in the pads of the feet. Stimulation of the ventromedial medullary reticular substance at the level of the obex abolished the VCR and the GSR. VCR could also be reduced by occlusion during prolonged stimulation of another spinal or visceral afferent pathway. Medulla stimulation was effective without itself causing a sympathetic discharge to the paw, showing that inhibition rather than occlusion was operative. Anterior cerebellar stimulation also inhibited the VCR. Carotid sinus nerve stimulation did not abolish the VCR. It is concluded that the effective mechanism includes a bulbospinal inhibitory path projecting on a spinal vasoconstrictor reflex arc. This arrangement is similar to the descending pathways inhibiting other spinal reflexes but the VCR-inhibitory path can be activated independently of them.

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