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Central α-adrenoceptors contribute to mustard oil-induced central sensitization in the rat medullary dorsal horn.
Wang, H; Xie, Y F; Chiang, C Y; Dostrovsky, J O; Sessle, B J.
Afiliação
  • Wang H; Department of Oral Physiology, Faculty of Dentistry, University of Toronto, Toronto, ON, Canada M5G 1G6.
Neuroscience ; 236: 244-52, 2013 Apr 16.
Article em En | MEDLINE | ID: mdl-23333675
ABSTRACT
Our previous studies have demonstrated that application of the inflammatory irritant mustard oil (MO) to the tooth pulp produces trigeminal central sensitization that includes increases in mechanoreceptive field size and responses to noxious stimuli and decrease in activation threshold in brainstem nociceptive neurons of trigeminal subnucleus caudalis (the medullary dorsal horn, MDH). The aim of the present study was to test if central noradrenergic processes are involved in the central sensitization of MDH neurons and if α1-adrenoceptors or α2-adrenoceptors or both are involved. In urethane/α-chloralose-anesthetized rats, the activity of extracellularly recorded and functionally identified single nociceptive neurons in the MDH was studied. Continuous intrathecal (i.t.) superfusion of the adrenergic modulator guanethidine and α-adrenoceptor blocker phentolamine or selective α1-adrenoceptor antagonist prazosin over the medulla strongly attenuated all three MO-induced parameters of central sensitization in the MDH nociceptive neurons, compared to phosphate-buffered saline (as vehicle control). In contrast, i.t. superfusion of the selective α2-adrenoceptor antagonist yohimbine had little effect on the mechanoreceptive field expansion and the decreased mechanical activation threshold, and indeed facilitated responses to noxious stimuli of sensitized nociceptive neurons. Superfusion of each of the four chemicals alone did not affect baseline nociceptive neuronal properties. These findings provide the first documentation of the involvement of central noradrenergic processes in MDH in the development of the central sensitization, and that α1- and α2-adrenoceptors may be differentially involved.
Assuntos

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Bulbo / Receptores Adrenérgicos / Sensibilização do Sistema Nervoso Central Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: Neuroscience Ano de publicação: 2013 Tipo de documento: Article

Texto completo: 1 Coleções: 01-internacional Base de dados: MEDLINE Assunto principal: Bulbo / Receptores Adrenérgicos / Sensibilização do Sistema Nervoso Central Tipo de estudo: Prognostic_studies Limite: Animals Idioma: En Revista: Neuroscience Ano de publicação: 2013 Tipo de documento: Article
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