Activation of purinergic receptor subtypes in the nucleus tractus solitarius elicits specific regional vascular response patterns

Barraco, Robin A.; O’Leary, Donal S.; Ergene, Erhan; Scislo, Tadeusz J.

doi:10.1016/0165-1838(96)00014-8

Cited by 65 publications

(68 citation statements)

References 29 publications

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“…Increases in HVC to pharmacological stimulation of P2 receptors in the NTS were associated with transitory hypotension and bradycardia [16,39], in opposition to rises in AP and HR in response to stimulation of the HDA. This paradox is possibly explained on the basis of differential mechanisms in control of HVC independent from regulation of HR and AP.…”

Section: Hindlimb Vasodilation In Alerting-defense Responses Is Mediamentioning

confidence: 90%

“…In anesthetized rats, stimulation of P2 receptors in the subpostremal NTS by microinjecting the P2x 1-3 agonist α,β-methylene ATP elicits hindlimb vasodilation (increase in HVC) associated with reductions in AP and HR [16]. In the RVLM, iontophoretic injections of different P2 agonists increases the firing rate of cardiovascular bulbospinal neurons [17].…”

Section: Introductionmentioning

confidence: 99%

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Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Korim

Ferreira-Neto

Pedrino

et al. 2012

Purinergic Signalling

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In the nucleus tractus solitarii (NTS) of rats, blockade of extracellular ATP breakdown to adenosine reduces arterial blood pressure (AP) increases that follow stimulation of the hypothalamic defense area (HDA). The effects of ATP on NTS P2 receptors, during stimulation of the HDA, are still unclear. The aim of this study was to determine whether activation of P2 receptors in the NTS mediates cardiovascular responses to HDA stimulation. Further investigation was taken to establish if changes in hindlimb vascular conductance (HVC) elicited by electrical stimulation of the HDA, or activation of P2 receptors in the NTS, are relayed in the rostral ventrolateral medulla (RVLM); and if those responses depend on glutamate release by ATP acting on presynaptic terminals. In anesthetized and paralyzed rats, electrical stimulation of the HDA increased AP and HVC. Blockade of P2 or glutamate receptors in the NTS, with bilateral microinjections of suramin (10 mM) or kynurenate (50 mM) reduced only the evoked increase in HVC by 75 % or more. Similar results were obtained with the blockade combining both antagonists. Blockade of P2 and glutamate receptors in the RVLM also reduced the increases in HVC to stimulation of the HDA by up to 75 %. Bilateral microinjections of kynurenate in the RVLM abolished changes in AP and HVC to injections of the P2 receptor agonist α,β-methylene ATP (20 mM) into the NTS. The findings suggest that HDA-NTS-RVLM pathways in control of HVC are mediated by activation of P2 and glutamate receptors in the brainstem in alerting-defense reactions.

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Section: Hindlimb Vasodilation In Alerting-defense Responses Is Mediamentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Korim

Ferreira-Neto

Pedrino

et al. 2012

Purinergic Signalling

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“…However, ATP can be easily converted to adenosine that binds to P1 purinergic receptors (classified as A1, A2, and A3) (3,4). Functional studies have shown that central purinergic mechanisms are involved in cardiac, respiratory and thermal regulation (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16). However, there is little information on the role of purinergic mechanisms in behavioral responses (17), including pathways involved in intracellular and extracellular thirst.…”

Section: Introductionmentioning

confidence: 99%

Antidipsogenic effects of central adenosine-5'-triphosphate

Faria

Sant'Ana

Menani

et al. 2009

Braz J Med Biol Res

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Besides other physiological functions, adenosine-5'-triphosphate (ATP) is also a neurotransmitter that acts on purinergic receptors. In spite of the presence of purinergic receptors in forebrain areas involved with fluid-electrolyte balance, the effect of ATP on water intake has not been investigated. Therefore, we studied the effects of intracerebroventricular (icv ) injections of ATP (100, 200 and 300 nmol/μL) alone or combined with DPCPX or PPADS (P1 and P2 purinergic antagonists, respectively, 25 nmol/μL) on water intake induced by water deprivation. In addition, the effect of icv ATP was also tested on water intake induced by intragastric load of 12% NaCl (2 mL/rat), acute treatment with the diuretic/natriuretic furosemide (20 mg/kg), icv angiotensin II (50 ng/μL) or icv carbachol (a cholinergic agonist, 4 nmol/μL), on sodium depletion-induced 1.8% NaCl intake, and on food intake induced by food deprivation. Male Holtzman rats (280-320 g, N = 7-11) had cannulas implanted into the lateral ventricle. Icv ATP (300 nmol/μL) reduced water intake induced by water deprivation (13.1 ± 1.9 vs saline: 19.0 ± 1.4 mL/2 h; P < 0.05), an effect blocked by pre-treatment with PPADS, but not DPCPX. Icv ATP also reduced water intake induced by NaCl intragastric load (5.6 ± 0.9 vs saline: 10.3 ± 1.4 mL/2 h; P < 0.05), acute furosemide treatment (0.5 ± 0.2 vs saline: 2.3 ± 0.6 mL/15 min; P < 0.05), and icv angiotensin II (2.2 ± 0.8 vs saline: 10.4 ± 2.0 mL/2 h; P < 0.05), without changing icv carbachol-induced water intake, sodium depletion-induced 1.8% NaCl intake and food deprivation-induced food intake. These data suggest that central ATP, acting on purinergic P2 receptors, reduces water intake induced by intracellular and extracellular dehydration.

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“…O NTS apresenta projeções diretas para o RVL, cujo significado funcional permanece ainda em grande parte desconhecido. No NTS, o ATP e a adenosina derivada do catabolismo extracelular atuam como importantes neurotransmissores / neuromoduladores na regulação do fluxo sangüíneo regional muscular e visceral 13,16,17 C nos membros posteriores, indicando que a neurotransmissão purinérgica é capaz de promover vasodilatação muscular. Nestes animais, a estimulação da HDA provoca hipertensão, bradicardia e vasodilatação muscular.…”

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Os Núcleos Vasomotores Do Bulbo E a Regulação Cardiovascular: Novas Evidências E Novas Questões

Cravo

Rosa²,

Kalassa³

et al. 2006

Medicina (Ribeirão Preto)

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RESUMO: Há mais de 30 anos foi proposto um modelo para explicar como o sistema nervoso central promove a regulação do sistema cardiovascular, onde os núcleos vasomotores do bulbo seriam as principais estruturas envolvidas no controle do reflexo cardiovascular. Segundo este modelo, o núcleo do trato solitário (NTS) é o primeiro núcleo a integrar as informações cardiovasculares vindas dos baroceptores e também parece integrar vias descendentes provenientes de núcleos superiores como o hipotálamo, importantes para as reações de alerta e defesa. Do NTS saem projeções excitatórias para a região caudoventrolateral (CVL) do bulbo, a qual inibe a região rostroventrolateral (RVL). Esta última região constitui a principal fonte de eferências excitatórias para os neurônios simpáticos pré-ganglionares (SPN), sendo responsá-vel pelo tonus simpático para o coração e vasos. Projeções importantes do CVL para estruturas diencefálicas (núcleo preóptico mediano, núcleo paraventricular do hipotálamo e núcleo supraóptico) também estão envolvidas no controle da composição e/ou volume do compartimento extracelular. A área depressora gigantocelular (GiDA) constitui outro possível centro vasomotor envolvido nos ajustes de fluxo sangüíneo por meio de projeções diretas para o SPN. No entanto, o meio pelo qual a GiDA exerce seu efeito vasodepressor ainda é desconhecido.Nos últimos 10 anos, nosso laboratório tem se dedicado a deslindar as vias e mecanismos neurais associados à regulação do fluxo sangüíneo visceral e muscular. Resultados obtidos ao longo destes estudos resultaram em evidências que são incompatíveis com o modelo proposto.Descritores: Pressão Arterial. NTS. RVL. CVL. 89 1-INTRODUÇÃOA perfusão do leito vascular capilar constitui um elemento essencial da homeostasia. É através do fluxo sangüíneo que percorre este território e das trocas que aí se realizam, que o interstício pode ser renovado, mantendo-se nas condições ideais para a homeostasia celular. A perfusão do leito capilar depende de níveis adequados de pressão sangüínea arterial, uma vez que esta constitui a força motriz que Capítulo IX

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Activation of purinergic receptor subtypes in the nucleus tractus solitarius elicits specific regional vascular response patterns

Cited by 65 publications

References 29 publications

Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Interaction of medullary P2 and glutamate receptors mediates the vasodilation in the hindlimb of rat

Antidipsogenic effects of central adenosine-5'-triphosphate

Os Núcleos Vasomotores Do Bulbo E a Regulação Cardiovascular: Novas Evidências E Novas Questões

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