| Registro completo |
| Provedor de dados: |
BJMBR
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| País: |
Brazil
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| Título: |
Blockade of NK-1 receptors in the lateral commissural nucleus tractus solitarii of awake rats had no effect on the cardiovascular responses to chemoreflex activation
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| Autores: |
Zhang,C.
Bonagamba,L.G.H.
Machado,B.H.
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| Data: |
2000-11-01
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| Ano: |
2000
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| Palavras-chave: |
Tachykinins
Cardiovascular regulation
Carotid chemoreceptors
Autonomic regulation
NK-1 receptors
Substance P
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| Resumo: |
The neurotransmission of the chemoreflex in the nucleus tractus solitarii (NTS), particularly of the sympatho-excitatory component, is not completely understood. There is evidence that substance P may play a role in the neurotransmission of the chemoreflex in the NTS. Microinjection of substance P (50 pmol/50 nl, N = 12, and 5 nmol/50 nl, N = 8) into the commissural NTS of unanesthetized rats produced a significant increase in mean arterial pressure (101 ± 1 vs 108 ± 2 and 107 ± 3 vs 115 ± 4 mmHg, respectively) and no significant changes in heart rate (328 ± 11 vs 347 ± 15 and 332 ± 7 vs 349 ± 13 bpm, respectively) 2 min after microinjection. Previous treatment with WIN, an NK-1 receptor antagonist (2.5 nmol/50 nl), microinjected into the NTS of a specific group of rats, blocked the pressor (11 ± 5 vs 1 ± 2 mmHg) and tachycardic (31 ± 6 vs 4 ± 3 bpm) responses to substance P (50 pmol/50 nl, N = 5) observed 10 min after microinjection. Bilateral microinjection of WIN into the lateral commissural NTS (N = 8) had no significant effect on the pressor (50 ± 4 vs 42 ± 6 mmHg) or bradycardic (-230 ± 16 vs -220 ± 36 bpm) responses to chemoreflex activation with potassium cyanide (iv). These data indicate that the activation of NK-1 receptors by substance P in the NTS produces an increase in baseline mean arterial pressure and heart rate. However, the data obtained with WIN suggest that substance P and NK-1 receptors do not play a major role in the neurotransmission of the chemoreflex in the lateral commissural NTS.
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| Tipo: |
Info:eu-repo/semantics/article
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| Idioma: |
Inglês
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| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2000001100018
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| Editor: |
Associação Brasileira de Divulgação Científica
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| Relação: |
10.1590/S0100-879X2000001100018
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| Formato: |
text/html
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| Fonte: |
Brazilian Journal of Medical and Biological Research v.33 n.11 2000
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| Direitos: |
info:eu-repo/semantics/openAccess
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