ORIGINAL RESEARCH published: 02 June 2016 doi: 10.3389/fphys.2016.00205 Frontiers in Physiology | www.frontiersin.org 1 June 2016 | Volume 7 | Article 205 Edited by: Valdir Andrade Braga, Federal University of Paraíba, Brazil Reviewed by: Simon McMullan, Macquarie University, Australia Josiane Campos Cruz, Federal University of Paraíba, Brazil *Correspondence: Gustavo R. Pedrino pedrino@pq.cnpq.br; gpedrino@gmail.com Specialty section: This article was submitted to Integrative Physiology, a section of the journal Frontiers in Physiology Received: 11 February 2016 Accepted: 20 May 2016 Published: 02 June 2016 Citation: Pinto IS, Mourão AA, da Silva EF, Camargo AS, Marques SM, Gomes KP, Fajemiroye JO, da Silva Reis AA, Rebelo ACS, Ferreira-Neto ML, Rosa DA, Freiria-Oliveira AH, Castro CH, Colombari E, Colugnati DB and Pedrino GR (2016) Blockade of Rostral Ventrolateral Medulla (RVLM) Bombesin Receptor Type 1 Decreases Blood Pressure and Sympathetic Activity in Anesthetized Spontaneously Hypertensive Rats. Front. Physiol. 7:205. doi: 10.3389/fphys.2016.00205 Blockade of Rostral Ventrolateral Medulla (RVLM) Bombesin Receptor Type 1 Decreases Blood Pressure and Sympathetic Activity in Anesthetized Spontaneously Hypertensive Rats Izabella S. Pinto 1 , Aline A. Mourão 1 , Elaine F. da Silva 1 , Amanda S. Camargo 1 , Stefanne M. Marques 1 , Karina P. Gomes 1 , James O. Fajemiroye 2 , Angela A. da Silva Reis 3 , Ana C. S. Rebelo 4 , Marcos L. Ferreira-Neto 5 , Daniel A. Rosa 1 , André H. Freiria-Oliveira 1 , Carlos H. Castro 1 , Eduardo Colombari 6 , Diego B. Colugnati 1 and Gustavo R. Pedrino 1 * 1 Department of Physiological Sciences, Center for Neuroscience and Cardiovascular Research, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil, 2 Postgraduate Programme in Pharmaceutical Sciences, Faculty of Pharmacy, Federal University of Goiás, Goiânia, Brazil, 3 Department of Biochemistry and Molecular Biology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil, 4 Department of Morphology, Biological Sciences Institute, Federal University of Goiás, Goiânia, Brazil, 5 Department of Physiology, College of Physical Education, Federal University of Uberlândia, Uberlândia, Brazil, 6 Department of Physiology and Pathology, School of Dentistry, São Paulo State University, Araraquara, Brazil Intrathecal injection of bombesin (BBS) promoted hypertensive and sympathoexcitatory effects in normotensive (NT) rats. However, the involvement of rostral 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 (BB 1 ) 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 < 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). BB 1 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 BB 1 receptors. This pathway might be involved in the maintenance of high levels of arterial blood pressure in SHR. Keywords: rostral ventrolateral medulla, bombesin, BB 1 receptors, BIM-23127, SHR