Renal sympathetic activation triggered by the rostral ventrolateral medulla is dependent of spinal cord AT1 receptors in Goldblatt hypertensive rats

Author(s)

Milanez, Maycon I. O. ^[1] ; Nishi, Erika E. ^[1] ; Mendes, Rodrigo ^[1] ; Rocha, Antonio A. ^[1] ; Bergamaschi, Cassia T. ^[1] ; Campos, Ruy R. ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Dept Physiol, Cardiovasc Div, Escola Paulista Med, Rua Botucatu 862, Ground Floor, BR-04023060 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Peptides; v. 146, DEC 2021.
• Web of Science Citations: 0

Abstract

Spinal cord neurons contribute to elevated sympathetic vasomotor activity in renovascular hypertension (2K1C), particularly, increased actions of angiotensin II. However, the origin of these spinal angiotensinergic inputs remains unclear. The present study aimed to investigate the role of spinal angiotensin II type 1 receptor (AT1) receptors in the sympathoexcitatory responses evoked by the activation of the rostral ventrolateral medulla (RVLM) in control and 2K1C Goldblatt rats. Hypertension was induced by clipping of the left renal artery. After 6 weeks, a catheter (PE-10) filled with losartan was inserted into the subarachnoid space and advanced to the T1011 vertebral level in urethane-anesthetized rats. The effects of glutamate microinjection into the RVLM on blood pressure (BP), heart rate (HR), and renal and splanchnic sympathetic nerve activity (rSNA and sSNA, respectively) were evaluated in the presence or absence of spinal AT1 blockade. Tachycardic, pressor, and renal sympathoexcitatory effects caused by RVLM activation were significantly blunted by losartan in 2K1C rats, but not in control rats. However, no differences were found in the gene expression of angiotensin-converting enzyme, angiotensinogen, and renin in the spinal cord segments between the groups. In conclusion, acute sympathoexcitation induced by RVLM activation is dependent on the spinal AT1 receptor in Goldblatt, but not in control, rats. The involvement of other central cardiovascular nuclei in spinal angiotensinergic actions, as well as the source of angiotensin II, remains to be determined in the Goldblatt model. (AU)

• FAPESP's process: 18/01898-4 - Evaluation of brain-spinal projections in the temporal establishment of renal sympathetic hyperactivation in Renovascular Hypertension
• Grantee: Maycon Igor de Oliveira Milanez
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 18/02671-3 - Functional and molecular actions of renal nerve in experimental chronic renal failure
• Grantee: Cassia Marta de Toledo Bergamaschi
• Support Opportunities: Regular Research Grants
• FAPESP's process: 19/25295-0 - Communication between the central nervous system and kidneys: cardiovascular, renal and autonomic influences in physiological and physiopathological conditions
• Grantee: Ruy Ribeiro de Campos Junior
• Support Opportunities: Research Projects - Thematic Grants