Control of breathing and blood pressure by parafacial neurons in conscious rats

Autor(es)

Takakura, Ana C. ^[1] ; Moreira, Thiago S. ^[2] ; De Paula, Patricia M. ^[3] ; Menani, Jose V. ^[3] ; Colombari, Eduardo ^[3]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Pharmacol, BR-05508900 Sao Paulo - Brazil

^[2] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05508900 Sao Paulo - Brazil

^[3] Sao Paulo State Univ UNESP, Sch Dent, Dept Physiol & Pathol, BR-14801903 Araraquara, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Experimental Physiology; v. 98, n. 1, p. 304-315, JAN 2013.
• Citações Web of Science: 13

Resumo

The retrotrapezoid nucleus (RTN), located in the parafacial region, contains glutamatergic neurons that express the transcriptor factor Phox2b and that are suggested to be central respiratory chemoreceptors. Studies in anaesthetized animals or in vitro have suggested that RTN neurons are important in the control of breathing by influencing respiratory rate, inspiratory amplitude and active expiration. However, the contribution of these neurons to cardiorespiratory control in conscious rats is not clear. Male Holtzman rats (280-300 g, n = 6-8) with bilateral stainless-steel cannulae implanted into the RTN were used. In conscious rats, the microinjection of the ionotropic glutamatergic agonist NMDA (5 pmol in 50 nl) into the RTN increased respiratory frequency (by 42%), tidal volume (by 21%), ventilation (by 68%), peak expiratory flow (by 24%) and mean arterial pressure (MAP, increased by 16 +/- 4, versus saline, 3 +/- 2 mmHg). Bilateral inhibition of the RTN neurons with the GABA(A) agonist muscimol (100 pmol in 50 nl) reduced resting ventilation (52 +/- 34, versus saline, 250 +/- 56 ml min(-1) kg(-1) with absolute values) and attenuated the respiratory response to hypercapnia and hypoxia. Muscimol injected into the RTN slightly reduced resting MAP (decreased by 13 +/- 7, versus saline, increased by 3 +/- 2 mmHg), without changing the effects of hypercapnia or hypoxia on MAP and heart rate. The results suggest that RTN neurons activate facilitatory mechanisms important to the control of ventilation in resting, hypoxic or hypercapnic conditions in conscious rats. (AU)

• Processo FAPESP: 10/19336-0 - Mecanismos pontinos envolvidos no controle cardiorrespiratório durante a ativação dos quimiorreceptores centrais ou periféricos
• Beneficiário: Thiago dos Santos Moreira
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• 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