PURINERGIC P2 RECEPTORS IN THE PARAVENTRICULAR NUCLEUS OF THE HYPOTHALAMUS ARE INVOLVED IN HYPEROSMOTIC-INDUCED SYMPATHOEXCITATION

Autor(es)

Ferreira-Neto, H. C. ; Ribeiro, I. M. R. ; Moreira, T. S. ; Yao, S. T. ; Antunes, V. R.

• Tipo de documento: Artigo Científico
• Fonte: Neuroscience; v. 349, p. 253-263, MAY 4 2017.
• Citações Web of Science: 1

Resumo

Increases in plasma osmolality activates the paraventricular nucleus of the hypothalamus (PVN) which in turn mounts a physiological response by increasing the release of arginine vasopressin and sympathetic nerve activity to end organs such as the kidney. The PVN expresses an abundance of purinergic receptors including P2X2 receptors. In the present study, we sought to determine (1) whether P2X2-expressing PVN neurons are activated by hypertonic saline or hypertonic mannitol and (2) what effects P2X receptor blockade has on sympathetic nerve activation mediated by a hyperosmotic stimulus. Male Wistar rats were randomly assigned to three groups and intravenously infused with either isotonic saline (0.154 M, 0.5 mL), hypertonic saline (3 M, 0.5 mL) or hypertonic mannitol (10% w/v, 0.5 mL). Significantly greater numbers of Fos positive cells were observed in the hypertonic saline (393 +/- 29)- and hypertonic mannitol (141 +/- 11)-infused rats compared with control, saline-treated, rats (47 +/- 2 neurons/PVN section). Furthermore, there was a significant increase in the number of activated (Fos-positive) P2X2 expressing PVN neurons in the hypertonic saline (65 +/- 7) and hyper tonic mannitol (37 +/- 7)-treated rats compared with controls (16 +/- 2). Microinjection of a P2X receptor antagonist, PPADS, within the PVN significantly attenuated sympathetic nerve activation driven by a hyperosmotic stimulus. The hyperosmotically induced increase in lumbar sympathetic nerve activity was significantly blunted after PPADS pretreatment. Collectively, our findings indicate that hyperosmotic stimulation activates a subset of P2X2 expressing PVN neurons that might facilitate increased sympathetic drive. (C) 2017 IBRO. Published by Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 10/05037-1 - Papel dos receptores purinérgicos do núcleo paraventricular do hipotálamo na hipertensão neurogênica
• Beneficiário: Hildebrando Candido Ferreira Neto
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 13/06206-0 - Estudo da expressão gênica de neuropeptídeos e mediadores inflamatórios em núcleos do eixo hipotálamo-tronco cerebral envolvidos no controle neural da pressão arterial de animais submetidos a dieta obesogênica
• Beneficiário: Vagner Roberto Antunes
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 16/21991-3 - Hipertensão secundária à alta ingestão de sal: estudo da sinalização purinérgica em células neuronais do hipotálamo e sua influência na atividade do sistema nervoso autônomo e pressão arterial
• Beneficiário: Vagner Roberto Antunes
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 10/17997-0 - Mecanismos da neurotransmissão purinérgica do hipotálamo sobre a atividade autonômica simpática e sua relação com a hipertensão neurogênica
• Beneficiário: Vagner Roberto Antunes
• Modalidade de apoio: Auxílio à Pesquisa - Regular