Document Detail

Effects of L-glutamate on the responses to nerve stimulation in rat isolated atria.
MedLine Citation:
PMID:  7522178     Owner:  NLM     Status:  MEDLINE    
In rat atria isolated with their sympathetic fibres the chronotropic responses to nerve stimulation with pulses of 2 ms duration were reduced in a concentration-dependent manner by 10 microM to 1 mM L-glutamate (Glu) and by 0.01 to 1.00 microM (R,S)-3-hydroxy-5-methoxyloxasole-4-propionic acid (AMPA), whereas they were unaffected by other agonists of Glu receptors such as 1 microM to 1 mM N-methyl-D-aspartic acid (NMDA), 10 microM to 1 mM kainate and 1 to 100 microM (+/-)-2-amino-4-phosphonobutyric acid (AP4). The reductions in the atrial responses to nerve stimulation caused by Glu were not accompanied by alterations in either the basal efflux of [3H]noradrenaline or its overflow in response to the stimulation. The sensitivity of the atria to exogenous noradrenaline was not modified by either Glu or AMPA. The decreases in the chronotropic responses caused by Glu and by AMPA were prevented by both the non-selective Glu receptor antagonist, 100 microM kynurenic acid, and the selective AMPA receptor antagonist, 10 to 50 microM 6,7-dinitroquinoxaline-2,3-dione (DNQX). In addition, the adenosine receptor antagonist, 8-phenyltheophylline (10 microM), as well as the muscarinic acetylcholine receptor antagonist, atropine (3 microM), prevented the inhibitory effects of both Glu and AMPA on the chronotropic responses of rat isolated atria. Since both adenosine and acetylcholine are known to exert negative inotropic and chronotropic effects in cardiac tissues, it is proposed that Glu could contribute, through the interaction with receptors of the AMPA type, to facilitate the release of adenosine and acetylcholine from the atria.(ABSTRACT TRUNCATED AT 250 WORDS)
P S Lorenzo; N V Butta; E Adler-Graschinsky
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Publication Detail:
Type:  In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of pharmacology     Volume:  258     ISSN:  0014-2999     ISO Abbreviation:  Eur. J. Pharmacol.     Publication Date:  1994 Jun 
Date Detail:
Created Date:  1994-10-19     Completed Date:  1994-10-19     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  1254354     Medline TA:  Eur J Pharmacol     Country:  NETHERLANDS    
Other Details:
Languages:  eng     Pagination:  253-60     Citation Subset:  IM    
Instituto de Investigaciones Farmacológicas, CONICET, Buenos Aires, Argentina.
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MeSH Terms
Adrenergic Fibers / physiology*
Aminobutyric Acids / pharmacology
Atrial Function
Electric Stimulation
Glutamates / pharmacology*
Glutamic Acid
Heart Atria / drug effects*,  innervation
Heart Rate / drug effects*
Kainic Acid / pharmacology
Muscarinic Antagonists
N-Methylaspartate / pharmacology
Norepinephrine / metabolism
Quinoxalines / pharmacology
Rats, Wistar
Receptors, Purinergic P1 / antagonists & inhibitors
alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / pharmacology
Reg. No./Substance:
0/Aminobutyric Acids; 0/Glutamates; 0/Muscarinic Antagonists; 0/Quinoxalines; 0/Receptors, Purinergic P1; 2379-57-9/FG 9041; 487-79-6/Kainic Acid; 51-41-2/Norepinephrine; 56-86-0/Glutamic Acid; 6323-99-5/2-amino-4-phosphonobutyric acid; 6384-92-5/N-Methylaspartate; 77521-29-0/alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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