Blockade of Rostral Ventrolateral Medulla (RVLM) Bombesin Receptor Type 1 Decreases Blood Pressure and Sympathetic Activity in Anesthetized Spontaneously Hypertensive Rats

Intrathecal injection of bombesin (BBS) promoted hypertensive and sympathoexcitatory effects in normotensive (NT) rats. However, the involvement of rostra' ventrolateral medulla (RVLM) in these responses is still unclear. In the present study, we investigated: (1) the effects of BBS injected bi...

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Detalles Bibliográficos
Autores: Pinto, Izabella S., Mourao, Aline A., Silva, Elaine F. da, Camargo, Amanda S., Marques, Stefanne M., Gomes, Karina P., Fajemiroye, James O., Silva Reis, Angela A. da, Rebelo, Ana C. S., Ferreira-Neto, Marcos L., Rosa, Daniel A., Freiria-Oliveira, Andre H., Castro, Carlos H., Colombari, Eduardo [UNESP], Colugnati, Diego B., Pedrino, Gustavo R.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2016
País:Brasil
Institución:Universidade Estadual Paulista (UNESP)
Repositorio:Repositório Institucional da UNESP
Idioma:inglés
OAI Identifier:oai:repositorio.unesp.br:11449/161555
Acceso en línea:http://dx.doi.org/10.3389/fphys.2016.00205
http://hdl.handle.net/11449/161555
Access Level:acceso abierto
Palabra clave:rostral ventrolateral medulla
bombesin
BB1 receptors
BIM-23127
SHR
Descripción
Sumario:Intrathecal injection of bombesin (BBS) promoted hypertensive and sympathoexcitatory effects in normotensive (NT) rats. However, the involvement of rostra' ventrolateral medulla (RVLM) in these responses is still unclear. In the present study, we investigated: (1) the effects of BBS injected bilaterally into RVLM on cardiorespiratory and sympathetic activity in NT and spontaneously hypertensive rats (SHR); (2) the contribution of RVLM BBS type 1 receptors (BB1) to the maintenance of hypertension in SHR. Urethane-anesthetized rats (1.2 g kg(-1), i.v.) were instrumented to record mean arterial pressure (MAP), diaphragm (DIA) motor, and renal sympathetic nerve activity (RSNA). In NT rats and SHR, BBS (0.3 mM) nanoinjected into RVLM increased MAP (33.9 +/- 6.6 and 37.1 +/- 4.5 mmHg, respectively; p 9 0.05) and RSNA (97.8 +/- 12.9 and 84.5 +/- 18.1%, respectively; p < 0.05). In SHR, BBS also increased DIA burst amplitude (115.3 +/- 22.7%; p 0.05). BB1 receptors antagonist (BIM-23127; 3 mM) reduced MAP (-19.9 +/- 4.4 mmHg; p < 0.05) and RSNA (-17.7 +/- 3.8%; p < 0.05) in SHR, but not in NT rats (-2.5 +/- 2.8 mmHg; -2.7 +/- 5.6%, respectively). These results show that BBS can evoke sympathoexcitatory and pressor responses by activating RVLM BB1 receptors. This pathway might be involved in the maintenance of high levels of arterial blood pressure in SHR.

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