Excitatory effects of nitric oxide within the rostral ventrolateral medulla of freely moving rats

Excitatory effects of nitric oxide within the rostral ventrolateral medulla of freely moving rats

Author Pinge, Marli Cardoso Martins Autor UNIFESP Google Scholar
Passy, Izabel Baraldi Autor UNIFESP Google Scholar
Lopes, Oswaldo Ubriaco Autor UNIFESP Google Scholar
Institution Universidade Federal de São Paulo (UNIFESP)
Abstract The aim of the present study was to examine the participation of NO in the rostral ventrolateral medulla (RVLM) of freely moving rats. We utilized NO donors and L-arginine, which were microinjected into the RVLM. Unilateral microinjection (100 nL) of 2.5 nmol sodium nitroprusside produced a biphasic response consisting of an initial, rapid increase in arterial pressure (AP) from 125+/-5 to 161+/-8 mm Hg (P<.01) and a second, long-lasting response with a progressive increase in AP (maximum Delta peak, 34+/-9 mm Hg; P<.01). Another NO donor, S-nitroso-N-acetylpenicillamine (SNAP; 2.5 nmol), also produced immediate hypertension from 118+/-5 mm Hg to 168+/-7 mm Hg (P<.01) but without the second, long-lasting response. L-Arginine (5, 24, and 140 nmol) produced a gradual increase in AP. L-Glutamate (5 nmol) microinjected into the RVLM produced an increase in AP from 122+/-9 mm Hg to 171+/-8 mm Hg (P<.01) and bradycardia from 342+/-10 to 315+/-8 beats/min. This AP response was significantly attenuated, from 115+/-7 to 128+/-9 mm Hg (P<.05), after microinjection of methylene blue (3 nmol) without alterations In heart rate. These results indicate that NO may have an excitatory effect on the RVLM of freely moving rats, probably in association with glutamatergic synapses via cGMP mechanisms.
Keywords amino acids
blood pressure, arterial
nitric oxide
rostral ventrolateral medulla
Language English
Date 1997-09-01
Published in Hypertension. Dallas: Amer Heart Assoc, v. 30, n. 3, p. 704-707, 1997.
ISSN 0194-911X (Sherpa/Romeo, impact factor)
Publisher Amer Heart Assoc
Extent 704-707
Origin https://doi.org/10.1161/01.HYP.30.3.704
Access rights Closed access
Type Article
Web of Science ID WOS:A1997XY88000033
URI http://repositorio.unifesp.br/11600/43846

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