Pressor response to pulsatile compression of the rostral ventrolateral medulla mediated by nitric oxide and c‐fos expression

• Published in: British journal of pharmacology Vol. 129; no. 5; pp. 859 - 864
• Main Authors: Morimoto, Satoshi, Sasaki, Susumu, Miki, Shigeyuki, Kawa, Tetsuyoshi, Itoh, Hiroshi, Nakata, Tetsuo, Takeda, Kazuo, Nakagawa, Masao
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 01.03.2000; Nature Publishing
• Subjects: Animals; Biological and medical sciences; Blood Pressure - physiology; compression; cyclic GMP; Cyclic GMP - physiology; c‐fos; Enzyme Inhibitors - pharmacology; Fundamental and applied biological sciences. Psychology; Genes, fos - genetics; Genes, fos - physiology; Glutamic Acid - pharmacology; Guanylate Cyclase - antagonists & inhibitors; Heart Rate - drug effects; Heart Rate - physiology; Hemodynamics. Rheology; Male; Medulla Oblongata - physiology; Microinjections; NG-Nitroarginine Methyl Ester - pharmacology; nitric oxide; Nitric Oxide - physiology; Nitric Oxide Synthase - antagonists & inhibitors; Nitric Oxide Synthase Type I; Oligodeoxyribonucleotides, Antisense - pharmacology; Rats; Rats, Wistar; RNA, Messenger - biosynthesis; Rostral ventrolateral medulla; sympathetic nerve activity; Sympathetic Nervous System - physiology; Vertebrates: cardiovascular system; Sympathetic nerve; Compression; Rat; Central nervous system; Phosphorus-oxygen lyases; Lyases; Activation; Glutamate receptor; Guanylate cyclase; Arterial pressure; Enzyme; Rodentia; Enzyme inhibitor; 3',5'-GMP; Gene expression; Antisense oligonucleotide; Nitric-oxide synthase; Heart rate; Vertebrata; Ventrolateral nucleus; Mammalia; Neuron; Animal; Nitric oxide; C-Onc gene; Oxidoreductases; Hemodynamics
• ISSN: 0007-1188; 1476-5381
• DOI: 10.1038/sj.bjp.0703121

It has been reported that neurovascular compression of the rostral ventrolateral medulla might be causally related to essential hypertension. Recently, we found that pulsatile compression of the rostral ventrolateral medulla increases sympathetic nerve activity and elevates arterial pressure via activation of glutamate receptors in rats. We also found that increases in sympathetic and cardiovascular activities by microinjection of L‐glutamate into the rostral ventrolateral medulla are mediated by c‐fos expression‐related substance(s) following activation of the nitric oxide‐cyclic GMP pathway. Herein, we investigated whether responses to pulsatile compression are mediated by local activation of the nitric oxide‐cyclic GMP pathway and/or c‐fos expression‐related substance(s) in rats. Increases in arterial pressure (15±1 mmHg), heart rate (9±1 b.p.m.), and sympathetic nerve activity (% change: 8.5±1.1%) induced by pulsatile compression were partially but significantly inhibited after local microinjection of a nitric oxide synthase inhibitor, L‐NG‐nitroarginine methyl ester (8±2 mmHg, 1±1 b.p.m., 4.0±1.3%; P<0.05 vs compression without pretreatment) or 7‐nitroindazole (7±2 mmHg, 2±1 b.p.m., 4.0±1.5%; P<0.05), or a soluble guanylate cyclase inhibitor, methylene blue (9±1 mmHg, 4±1 b.p.m., 4.1±1.4%; P<0.05). In addition, increases in arterial pressure, heart rate, and sympathetic nerve activity by pulsatile compression were significantly reduced 6 h after microinjection of antisense oligodeoxynucleotide to c‐fos mRNA (2±2 mmHg, 2±1 b.p.m., 1.0±1.0%; P<0.05 vs sense oligodeoxynucleotide). These results suggest that increases in sympathetic and cardiovascular activities induced by pulsatile compression of the rostral ventrolateral medulla are mediated, at least in part, by local activation of the nitric oxide‐cyclic GMP pathway and c‐fos expression‐related substance(s) in rats. British Journal of Pharmacology (2000) 129, 859–864; doi:10.1038/sj.bjp.0703121