Nitric oxide release in the nucleus tractus solitarius during and after bilateral common carotid artery occlusion.
1. The purpose of the present study was to investigate the effect of bilateral common carotid artery occlusion (BCCAO) on cardiovascular responses and nitric oxide (NO) formation in the nucleus tractus solitarius (NTS). 2. Twenty-three adult cats were anaesthetized intraperitoneally with urethane (400 mg/kg) and alpha-chloralose (40 mg/kg). The femoral artery was cannulated to allow monitoring of systemic arterial pressure (SAP) and heart rate (HR). The femoral vein was cannulated for intravenous drug administration. 3. Extracellular NO levels in the NTS were measured by in vivo voltammetry using an NO microsensor combined with a microcomputer-controlled apparatus. 4. Microinjection of l-arginine (30 nmol) into the NTS produced hypotension and NO release. This effect of l-arginine was not changed by 2 min of BCCAO. 5. Bilateral common carotid artery occlusion produced increases in SAP and NO levels. These effects were more apparent in vagotomized than in intact animals. 6. The onset latency of BCCAO-induced changes in SAP levels (8.4 +/- 2.5 s) was longer than that for changes in NO (4.7 +/- 1.7 s). 7. Bilateral common carotid artery occlusion induced hypertension and NO release in the NTS of intact and vagotomized animals. These cardiovascular and NO responses to BCCAO were significantly attenuated by NG-nitro-l-arginine methyl ester (10 mg/kg, i.v.) and MK-801 (2.5 mg/kg, i.v.). These data suggest that NO synthase and activation of N-methyl-d-aspartate receptors are involved in the cardiovascular and NO responses to BCCAO.
Wu
Wun-Chin
WC
Department of Electronic Engineering, National Penghu Institute of Technology, Penghu and Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
Chai
Chok-Yung
CY
D000818:Animals; D001157:Arterial Occlusive Diseases / Q000150:complications*; D001794:Blood Pressure; D002340:Carotid Artery Diseases / Q000150:complications*; D017536:Carotid Artery, Common; D002415:Cats; D016291:Dizocilpine Maleate / Q000494:pharmacology; D005260:Female; D006973:Hypertension / Q000209:etiology / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D016194:Receptors, N-Methyl-D-Aspartate / Q000819:agonists; D017552:Solitary Nucleus / Q000378:metabolism*; D013997:Time Factors
D016194:Receptors, N-Methyl-D-Aspartate; D009569:Nitric Oxide; D016291:Dizocilpine Maleate; D019001:Nitric Oxide Synthase; D019331:NG-Nitroarginine Methyl Ester