Spinal seizures evoked by sudden cooling of amphibian isolated spinal cords: Involvement of excitatory amino acids

Daló, Nelson L.; Larson, Alice A.

doi:10.1016/0011-2240(91)90031-i

Cited by 6 publications

(9 citation statements)

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“…1995b). This high sensitivity of tropical toads to glutamate may explain the neuronal injury found during cooling which caused a release of excitatory amino acids as was demonstrated using spinal cord slices (Daló & Larson 1991) and mammalian cultured neurons cooled to 10 °C (Craenen et al. 1996).…”

Section: Discussionmentioning

confidence: 94%

“…In B. marinus , sudden cooling (<10 °C) of the isolated spinal cord induces seizure. The tonic phase of this convulsion is effectively abolished by glutamate receptor antagonists (Daló & Larson 1991) and by common anticonvulsant drugs (Piña‐Crespo & Daló 2006). However, a clear difference is found among species using electrophysiological measurements.…”

Section: Discussionmentioning

confidence: 99%

“…In addition to these differences in neuronal responses to cooling, there are biochemical differences among species when neuronal tissues are submitted to cooling. For instance, cooling of spinal cord slices from tropical amphibians to 4 °C releases excitatory amino acids, but the same protocol fails to produce significant release of excitatory amino acids in spinal cord slices of North American frogs (Daló & Larson 1991).…”

Section: Discussionmentioning

confidence: 99%

“…During these experiments, the isolated spinal cord attached to the hind limbs was cooled by placing it into a cold Ringer's bath maintained at the desired temperature using a refrigerated bath circulator (Haake, Model FK, Haake Instruments, Saddle Brook, NJ, USA). The contractions of the gastrocnemius muscle were recorded, as previously described, using a myograph connected to a physiograph (Narco‐Bio System, Austin, TX, USA) (Daló & Larson 1991). South American toads ( B. marinus ) weighting 79–295 g (mean = 149, n = 97) were used.…”

Section: Methodsmentioning

confidence: 99%

“…1994, 1995). In tropical amphibians such as Bufo marinus , cooling of the spinal cord at temperatures below 10 °C produces strong seizure activity (Ozorio de Almeida 1943), that is accompanied by a massive release of the excitatory neurotransmitters glutamate and aspartate (Daló & Larson 1991). This species of amphibian is highly sensitive to cold exposure showing not only cellular changes, but also behavioural changes.…”

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confidence: 99%

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Motor impairment and neuronal damage following hypothermia in tropical amphibians

Daló

Bracho

Piña‐Crespo

2006

Int J Experimental Path

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Although the induction of mild to moderate cerebral hypothermia in mammals can have neuroprotective activity, some deleterious effects have been described when inducing deep hypothermia during cooling of the brain. In the spinal cord, rapid deep cooling can induce seizure activity accompanied by release of the excitatory neurotransmitters, glutamate and aspartate. We used cold-sensitive tropical amphibians as a model to determine (a) the critical temperature inside the central nervous system necessary to induce seizures during rapid cooling; (b) the survival rate during slow deep cooling of the whole animal; and (c) whether deep cooling can cause neuronal cell damage. Seizures induced by deep rapid (or=30 min) deep cooling of the whole animal (12 h at 2-3 degrees C), around 70% of animals died. Spinal reflexes were enhanced when temperatures within the spinal cord reached between 9.0 degrees C and 11.6 degrees C. A fivefold increase in blood glucose level was observed during slow deep cooling. Recovery after slow deep cooling was accompanied by motor impairment and the main histological findings were condensation of the cytoplasm and nuclear pyknosis. Severe neuronal cell damage was characterized by swelling, vacuolated cytoplasm with distended neuronal bodies. These results indicate that deep cooling can easily induce neuronal cell damage in the central nervous system of cold-sensitive animals. They also warn us to the potential sequels associated with the use of deep brain cooling as a neuroprotective strategy.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

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