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rodent

Rodent

Rodents (from Latin rodere, “to gnaw”) are mammals of the order Rodentia, which are characterized by a single pair of unremittingly growing incisors in each of the upper and lower jaws. About forty percent of all mammal species are rodents; they are found in vast numbers on all continents except Antarctica. They are the most diversified mammalian order and live in a variety of terrestrial habitats, including human-made environments. There are species that are arboreal, fossorial (burrowing), and semiaquatic. Well-known rodents include mice, rats, squirrels, prairie dogs, porcupines, beavers, guinea pigs, hamsters, and capybaras. Other animals such as rabbits, hares and pikas were once included with them, but are now considered to be in a separate order, Lagomorpha.


As rodents are not suitable for comprehensive electroencephalography (EEG) investigation via scalp or subdural electrodes recording because of their very small head, a larger primate model that closely recapitulates symptoms of patients with Temporal Lobe Epilepsy (TLE) is needed, and here we describe a rhesus monkey model resembling chronic TLE.

Young male adult rhesus monkeys received delayed kainic acid (KA) injections in their right amygdala via an ommaya reservoir. Additionally, bilateral subdural electrodes were implanted over the parietal-temporal lobes for further electrophysiology investigation, and multiple KA injections were given with continuous video-scalp EEG monitoring.

Monkeys developed spontaneous recurrent seizures (SRSs) that showed little motor clinical signs but symptoms mimicking temporal lobe absence appeared several weeks after KA injection. Both interictal spikes and onset of ictal discharges indicated a primary epileptic zone in the right temporal region and secondary discharges were detected later.

Through a modified protocol of unilateral repetitive intra-amygdala KA injection, a rhesus monkey model with high similarity to chronic TLE was developed.

Results indicated that acute convulsive status epilepticus were not necessary for developing a chronic epilepsy condition in rhesus monkey. And after KA injection, animals showed a progressive nature characterized by secondary discharges 1).


Rodent models are numerous as well but are not as useful as primate models and not comparable with SAH in humans 2) 3).

The validity of using MRI to show infarction in rodents was studied using a middle cerebral artery occlusion model by various working groups 4) 5).

Books

Experimental Neurosurgery in Animal Models (Neuromethods) From Humana Press

This volume provides a full explanation and technical details to perform surgical techniques properly on small and large animal models. The first six chapters of Experimental Neurosurgery in Animal Models focus primarily on the brain, while the next six chapters concern the spinal cord in rodents. The last four chapters provide a description of operative procedures in large animals. Written for the popular Neuromethods series, chapters include the kind of detail and key implementation advice that ensures successful results in the laboratory.

Authoritative and practical, Experimental Neurosurgery in Animal Models aims to ensure successful results in the further study of this vital field.

1)
Chi Y, Wu B, Guan J, Xiao K, Lu Z, Li X, Xu Y, Xue S, Xu Q, Rao J, Guo Y. Repetitive Unilateral Intra-amygdala Kainic Acid Injection Establishes A Rhesus Monkey Model of Chronic Temporal Lobe Epilepsy. Brain Res Bull. 2017 Aug 22. pii: S0361-9230(16)30472-5. doi: 10.1016/j.brainresbull.2017.08.010. [Epub ahead of print] PubMed PMID: 28842304.
2)
Gules I, Satoh M, Clower BR, Nanda A, Zhang JH. Comparison of three rat models of cerebral vasospasm. Am J Physiol Heart Circ Physiol 2002;283(06):H2551–H2559
3)
Meguro T, Clower BR, Carpenter R, Parent AD, Zhang JH. Improved rat model for cerebral vasospasm studies. Neurol Res 2001;23 (07):761–766
4)
van den Bergh WM, Schepers J, Veldhuis WB, Nicolay K, Tulleken CA, Rinkel GJ. Magnetic resonance imaging in experimental subarachnoid haemorrhage. Acta Neurochir (Wien) 2005;147 (09):977–983; discussion 983
5)
Hofmeijer J, Veldhuis WB, Schepers J, et al. The time course of ischemic damage and cerebral perfusion in a rat model of space-occupying cerebral infarction. Brain Res 2004;1013(01): 74–82
rodent.txt · Last modified: 2018/08/09 19:47 by administrador