Intravenous NBQX inhibits spontaneously occurring sympathetic nerve activity and reduces blood pressure in cats.
2,3-Dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline (NBQX) has been demonstrated to be a specific and competitive non-N-methyl-D-aspartate (non-NMDA) glutamate receptor antagonist. Our previous data obtained with the NMDA receptor antagonist MK-801 indicate that blockade of the NMDA receptor affects blood pressure. The purpose of this study was to determine whether the same is true with blockade of the non-NMDA receptor. For this purpose we administered three doses of NBQX (1, 3 and 10 mg/kg i.v.) to anesthetized, artificially ventilated and paralyzed cats while monitoring spontaneously occurring cardiac sympathetic nerve activity, arterial blood pressure and heart rate. The 1 mg/kg dose of NBQX i.v. reduced both sympathetic nerve activity (-29 +/- 7%, P < 0.05, n = 4) and blood pressure (-27 +/- 5 mmHg, P < 0.05). Injection of 3 mg/kg NBQX produced a greater decrease in sympathetic nerve activity (-78 +/- 11%, P < 0.01, n = 8) and mean arterial pressure (-47 +/- 5 mmHg) and also reduced heart rate (-11 +/- 2 beats/min, P < 0.01). The depressant effects of NBQX on sympathetic nerve activity, blood pressure and heart rate were similar regardless of whether activity was recorded from pre- or postganglionic cardiac nerves, or from animals subjected to baroreceptor denervation.(ABSTRACT TRUNCATED AT 250 WORDS)
Chen
K
K
Department of Pharmacology, Georgetown University Medical Center, Washington, DC 20007.
Hernandez
Y M
YM
Dretchen
K L
KL
Gillis
R A
RA
D000818:Animals; D017763:Autonomic Denervation; D001794:Blood Pressure / Q000187:drug effects*; D002415:Cats; D003864:Depression, Chemical; D004594:Electrophysiology; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D007262:Infusions, Intravenous; D008297:Male; D011311:Pressoreceptors / Q000187:drug effects / Q000502:physiology; D011810:Quinoxalines / Q000008:administration & dosage / Q000494:pharmacology*; D018091:Receptors, AMPA / Q000037:antagonists & inhibitors*; D013564:Sympathetic Nervous System / Q000187:drug effects*; D013565:Sympatholytics / Q000494:pharmacology*
D011810:Quinoxalines; D018091:Receptors, AMPA; D013565:Sympatholytics; C062865:2,3-dioxo-6-nitro-7-sulfamoylbenzo(f)quinoxaline