Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/14897

TitleResponse properties of nociceptive neurons in the caudal ventrolateral medulla (CVLM) in monoarthritic and healthy control rats : modulation of responses by the paraventricular nucleus of the hypothalamus (PVN)
Author(s)Ribeiro, Filipa Pinto
Ansah, Osei B.
Almeida, Armando
Pertovaara, Antti
KeywordsCaudal ventrolateral medulla
Arthritic pain
Descending modulation
Hypothalamus
Issue date1-Jul-2011
PublisherElsevier
JournalBrain Research Bulletin
Abstract(s)We characterized response properties of neurons in the caudal ventrolateral medulla (CVLM), a structure involved in pain modulation. Electrophysiological recordings were performed in pentobarbitoneanesthetized control and monoarthritic rats. Noxious pinch, heat, cold and colorectal distension were used for peripheral test stimulation. To study central modulation of CVLM neurons and role in mediating descending pain regulation from the hypothalamus, glutamate was administered into the paraventricular nucleus of the hypothalamus (PVN). CVLM neurons gave excitatory, inhibitory or no response to noxious test stimulation. Response patterns for part of the neurons varied with submodality of test stimulation; e.g., a cell with an excitatory response to heat could give no or an inhibitory response to cold. Arthritis induced cell type-dependent changes in the spontaneous activity, most prominent of which was increased discharge rate of CVLM cells with an excitatory response to noxious stimulation. Significant arthritis-induced changes were also observed in the magnitudes of the nociceptive responses, among which was an increase in the pinch-induced excitatory response. Glutamate in the PVN of arthritic but not control animals suppressed the excitatory responses of CVLM cells, independent of the submodality of test stimulation and without influence on their spontaneous discharge rates. The results indicate that CVLM neurons give differential responses to noxious stimulation. Arthritis induces changes in response properties of CVLM neurons and in their central regulation by the PVN. These findings are in line with the evidence indicating that the CVLM plays a role in processing of nociceptive signals under inflammatory as well as control conditions.
TypeArticle
URIhttp://hdl.handle.net/1822/14897
DOI10.1016/j.brainresbull.2011.06.014
ISSN0361-9230
Publisher versionhttp://dx.doi.org/10.1016/j.brainresbull.2011.06.014
Peer-Reviewedyes
AccessOpen access
Appears in Collections:ICVS - Artigos em Revistas Internacionais com Referee

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