Purinergic receptor blockade in the retrotrapezoid nucleus attenuates the respiratory chemoreflexes in awake rats

Autor(es)

Barna, B. F. ^[1] ; Takakura, A. C. ^[2] ; Mulkey, D. K. ^[3] ; Moreira, T. S. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, Prof Lineu Prestes Av 1524, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Sao Paulo, Inst Biomed Sci, Dept Pharmacol, Prof Lineu Prestes Av 1524, BR-05508000 Sao Paulo, SP - Brazil

^[3] Univ Connecticut, Dept Physiol & Neurobiol, Storrs, CT 06269 - USA

• Tipo de documento: Artigo Científico
• Fonte: ACTA PHYSIOLOGICA; v. 217, n. 1, p. 80-93, MAY 2016.
• Citações Web of Science: 12

Resumo

AimRecent evidence suggests that adenosine triphosfate (ATP)-mediated purinergic signalling at the level of the rostral ventrolateral medulla contributes to both central and peripheral chemoreceptor control of breathing and blood pressure: neurones in the retrotrapezoid nucleus (RTN) function as central chemoreceptors in part by responding to CO2-evoked ATP release by activation of yet unknown P2 receptors, and nearby catecholaminergic C1 neurones regulate blood pressure responses to peripheral chemoreceptor activation by a P2Y1 receptor-dependent mechanism. However, potential contributions of purinergic signalling in the RTN to cardiorespiratory function in conscious animals have not been tested. MethodsCardiorespiratory activity of unrestrained awake rats was measured in response to RTN injections of ATP, and during exposure to hypercapnia (7% CO2) or hypoxia (8% O-2) under control conditions and after bilateral RTN injections of P2 receptor blockers (PPADS or MRS2179). ResultsUnilateral injection of ATP into the RTN increased cardiorespiratory output by a P2-recepor-dependent mechanism. We also show that bilateral RTN injections of a non-specific P2 receptor blocker (pyridoxal-phosphate-6-azophenyl-2,4-disulfonate (PPADS) reduced the ventilatory response to hypercapnia (7% CO2) and hypoxia (8% O-2) in unanesthetized rats. Conversely, bilateral injections of a specific P2Y1 receptor blocker (MRS2179) into the RTN had no measurable effect on ventilatory responses elicited by hypercapnia or hypoxia. ConclusionThese data exclude P2Y1 receptor involvement in the chemosensory control of breathing at the level of the RTN and show that ATP-mediated purinergic signalling contributes to central and peripheral chemoreflex control of breathing and blood pressure in awake rats. (AU)

• Processo FAPESP: 12/10337-0 - Mecanismos neurais envolvidos na sinalização purinérgica no controle da quimiossensibilidade central e periférica
• Beneficiário: Bárbara Falquetto
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 10/09776-3 - Mecanismos neurais envolvidos na geração do ritmo expiratório: possível envolvimento do núcleo retrotrapezoide e da região parafacial
• Beneficiário: Ana Carolina Takakura Moreira
• Modalidade de apoio: Auxílio à Pesquisa - Jovens Pesquisadores
• Processo FAPESP: 09/54888-7 - Mecanismos neurais envolvidos na quimiorrecepção
• Beneficiário: Eduardo Colombari
• Modalidade de apoio: Auxílio à Pesquisa - Temático
• Processo FAPESP: 13/10573-8 - Mecanismos neurais da superfície ventral do bulbo envolvidos na quimiorrecepção
• Beneficiário: Thiago dos Santos Moreira
• Modalidade de apoio: Auxílio à Pesquisa - Regular