The role of the paratrigeminal nucleus in the pressor response to sciatic nerve stimulation in the rat

The role of the paratrigeminal nucleus in the pressor response to sciatic nerve stimulation in the rat

Author Caous, Cristofer André Autor UNIFESP Google Scholar
Koepp, Janice Google Scholar
Couture, Rejean Google Scholar
Balan, Antonio Claudir Autor UNIFESP Google Scholar
Lindsey, Charles Julian Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Inst Israelita Ensino & Pesquisa Albert Einstein
Univ Montreal
Abstract The paratrigeminal nucleus (Pa5), an input site for spinal, trigeminal, vagus and glossopharyngeal afferents, is a recognized site for orofacial nociceptive sensory processing. It has efferent connections to brain structures associated with nociception and cardiorespiratory functions. This study aimed at determining the function of the Pa5 on the cardiovascular component of the somatosensory reflex (SSR) to sciatic nerve stimulation (SNS) in paralyzed and artificially-ventilated rats following Pa5 chemical lesions (ibotenic acid), synaptic transmission blockade (CoCl(2)), local anaesthetics (lidocaine) or desensitization of primary afferent fibers (capsaicin). the pressor response to sciatic nerve stimulation at 0.6 mA and 20 Hz (14 +/- 1 mm Hg) was strongly attenuated by contra-(-80%) or bilateral (-50%) paratrigeminal nucleus lesions. Ipsilateral Pa5 lesions only attenuated the response to 0.1 mA, 20 Hz SNS (-55%). Cobalt chloride or lidocaine injected in the contralateral paratrigeminal nucleus also attenuated the SSR. in capsaicin-treated animals, the pressor responses to 0.1 mA were abolished, whereas the responses to SNS at 0.6 mA were increased from 65 to 100% depending on the stimulus frequency. the paratrigeminal nucleus receives both, excitatory and inhibitory components; the later apparently involving capsaicin-sensitive fiber inputs mostly to the ipsilateral site whereas the capsaicin insensitive excitatory components that respond to high or low frequency stimulation, respectively, target the contralateral and ipsilateral sites. Thus, the paratrigeminal nucleus mediates excitatory and inhibitory components of the somatosensory reflex, representing a primary synapse site in the brain for nociceptive inputs from the sciatic innervation field. (C) 2008 Published by Elsevier B.V.
Keywords Nociception
Cardiovascular reflex
Sciatic nerve
Primary afferent fibers
Synaptic transmission
Paratrigeminal nucleus lesion
Language English
Date 2008-06-01
Published in Autonomic Neuroscience-basic & Clinical. Amsterdam: Elsevier B.V., v. 140, n. 1-2, p. 72-79, 2008.
ISSN 1566-0702 (Sherpa/Romeo, impact factor)
Publisher Elsevier B.V.
Extent 72-79
Access rights Closed access
Type Article
Web of Science ID WOS:000257527700010

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