Data/hora: 04/06/2024 05:47:08

Provedor de dados: 	56	
País: 	Brazil	
Título: 	Respiratory effects of kynurenic acid microinjected into the ventromedullary surface of the rat	
Autores: 	Tolentino-Silva,F.P.; Russo,A.K.; Cravo,S.L.; Lopes,O.U.	
Data: 	1998-10-01	
Ano: 	1998	
Palavras-chave: 	Ventral surface of the medulla; Breathing pattern; Cardiorespiratory control; Kynurenic acid; Rat.	
Resumo: 	Several studies demonstrate that, within the ventral medullary surface (VMS), excitatory amino acids are necessary components of the neural circuits involved in the tonic and reflex control of respiration and circulation. In the present study we investigated the cardiorespiratory effects of unilateral microinjections of the broad spectrum glutamate antagonist kynurenic acid (2 nmol/200 nl) along the VMS of urethane-anesthetized rats. Within the VMS only one region was responsive to this drug. This area includes most of the intermediate respiratory area, partially overlapping the rostral ventrolateral medulla (IA/RVL). When microinjected into the IA/RVL, kynurenic acid produced a respiratory depression, without changes in mean arterial pressure or heart rate. The respiratory depression observed was characterized by a decrease in ventilation, tidal volume and mean inspiratory flow and an increase in respiratory frequency. Therefore, the observed respiratory depression was entirely due to a reduction in the inspiratory drive. Microinjections of vehicle (200 nl of saline) into this area produced no significant changes in breathing pattern, blood pressure or heart rate. Respiratory depression in response to the blockade of glutamatergic receptors inside the rostral VMS suggests that neurons at this site have an endogenous glutamatergic input controlling the respiratory cycle duration and the inspiratory drive transmission.	
Tipo: 	Info:eu-repo/semantics/other	
Idioma: 	Inglês	
Identificador: 	http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X1998001000016	
Editor: 	Associação Brasileira de Divulgação Científica	
Relação: 	10.1590/S0100-879X1998001000016	
Formato: 	text/html	
Fonte: 	Brazilian Journal of Medical and Biological Research  v.31 n.10 1998	
Fonte: 	info:eu-repo/semantics/openAccess