Consulta: subjectFacets:"Ventrolateral medulla"
Registros recuperados: 4
Data/hora: 28/05/2024 15:13:40

Excitatory amino acid receptor blockade within the caudal pressor area and rostral ventrolateral medulla alters cardiovascular responses to nucleus raphe obscurus stimulation in rats
Provedor de dados: Brazilian Journal of Medical and Biological Research
Autores: Silva,N.F.; Pires,J.G.P.; Dantas,M.A.; Futuro Neto,H.A.
Pressor responses elicited by stimulation of the nucleus raphe obscurus (NRO) depend on the integrity of the rostral ventrolateral medulla (RVLM). Therefore, to test the participation of excitatory amino acid (EAA) receptors in the cardiovascular responses evoked by NRO stimulation (1 ms, 100 Hz, 40-70 µA, for 10 s), the EAA antagonist kynurenic acid (Kyn) was microinjected at different sites in the ventrolateral medullar surface (2.7 nmol/200 nl) of male Wistar rats (270-320 g, N = 39) and NRO stimulation was repeated. The effects of NRO stimulation were: hypertension (deltaMAP = +43 ± 1 mmHg, P&lt;0.01), bradycardia (deltaHR = -30 ± 7 bpm, P&lt;0.01) and apnea. Bilateral microinjection of Kyn into the RVLM, which did not change baseline parameters,...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Raphe nuclei; Electrical stimulation; Ventrolateral medulla; Caudal pressor area; Excitatory amino acid receptors; Kynurenic acid; Blood pressure.
Ano: 2002
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2002001000019

Cardiovascular responses to microinjections of GABA or anesthetics into the rostral ventrolateral medulla of conscious and anesthetized rats
Provedor de dados: Brazilian Journal of Medical and Biological Research
Autores: Lacerda,J.E.C.; Campos,R.R.; Araujo,G.C.; Andreatta-Van Leyen,S.; Lopes,O.U.; Guertzenstein,P.G.
The rostral ventrolateral medulla (RVLM) contains neurons involved in tonic and reflex control of arterial pressure. We describe the effects of gamma-aminobutyric acid (GABA) and anesthetics injected into the RVLM of conscious and urethane (1.2 g/kg, iv) anesthetized Wistar rats (300-350 g). In conscious rats, bilateral microinjection of GABA (50 nmol/200 nl) induced a small but significant decrease in blood pressure (from 130 ± 3.6 to 110 ± 5.6 mmHg, N = 7). A similar response was observed with sodium pentobarbital microinjection (24 nmol/200 nl). However, in the same animals, the fall in blood pressure induced by GABA (from 121 ± 8.9 to 76 ± 8.8 mmHg, N = 7) or pentobarbital (from 118 ± 4.5 to 57 ± 11.3 mmHg, N = 6) was significantly increased after...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Vasomotor tone; Ventrolateral medulla; RVLM; GABA; Conscious rats.
Ano: 2003
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2003000900019

Cardiovascular and respiratory responses to microinjection of L-glutamate into the caudal pressor area in conscious and anesthetized rats
Provedor de dados: Brazilian Journal of Medical and Biological Research
Autores: Silva,N.F.; Pires,J.G.P.; Campos,R.R.; Futuro Neto,H.A.
The role of the caudal pressor area (CPA) in the maintenance of vasomotor tonus in anesthetized and decerebrate animals has been clearly established. In conscious animals, however, the participation of CPA in the cardiovascular control remains to be fully elucidated. In the present study, unilateral L-glutamate (L-Glu) (10 and/or 20 nmol/70 nl) microinjection into CPA, in conscious male Wistar rats (250-280 g) caused a significant increase in mean arterial blood pressure (MAP; control: 112 ± 1.9 mmHg; after 20 nmol L-Glu: 139 ± 4.5 mmHg, N = 12, P&lt;0.05) and respiratory rate (control: 81 ± 3.5 breaths/min; after 10 nmol L-Glu: 92 ± 3 breaths/min, P&lt;0.05; after 20 nmol L-Glu: 104 ± 5 breaths/min, N = 6, P&lt;0.05). The subsequent anesthesia with...
Tipo: Info:eu-repo/semantics/other
Palavras-chave: Caudal pressor area; Ventrolateral medulla; Blood pressure; L-glutamate; Respiration.
Ano: 2001
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2001001200013

Central chemoreceptors and neural mechanisms of cardiorespiratory control
Provedor de dados: Brazilian Journal of Medical and Biological Research
Autores: Takakura,A.C.; Damasceno,R.S.; Falquetto,B.; Totola,L.T.; Sobrinho,C.R.; Ragioto,D.T.; Zolezi,F.P.
The arterial partial pressure (P CO2) of carbon dioxide is virtually constant because of the close match between the metabolic production of this gas and its excretion via breathing. Blood gas homeostasis does not rely solely on changes in lung ventilation, but also to a considerable extent on circulatory adjustments that regulate the transport of CO2 from its sites of production to the lungs. The neural mechanisms that coordinate circulatory and ventilatory changes to achieve blood gas homeostasis are the subject of this review. Emphasis will be placed on the control of sympathetic outflow by central chemoreceptors. High levels of CO2 exert an excitatory effect on sympathetic outflow that is mediated by specialized chemoreceptors such as the neurons...
Tipo: Info:eu-repo/semantics/article
Palavras-chave: Chemoreflex; Cardiorespiratory responses; Ventrolateral medulla; Sympathetic nerve activity; Phrenic nerve activity.
Ano: 2011
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2011000900009