HYDROGEN PEROXIDE ATTENUATES THE DIPSOGENIC, RENAL AND PRESSOR RESPONSES INDUCED BY CHOLINERGIC ACTIVATION OF THE MEDIAL SEPTAL AREA

Author(s)

Melo, M. R. ^[1] ; Menani, J. V. ^[1] ; Colombari, E. ^[1] ; Colombari, D. S. A. ^[1]

Affiliation

^[1] Sao Paulo State Univ, UNESP, Sch Dent, Dept Physiol & Pathol, BR-14801903 Araraquara, SP - Brazil

• Document type: Journal article
• Source: Neuroscience; v. 284, p. 611-621, JAN 22 2015.
• Web of Science Citations: 6

Abstract

Cholinergic activation of the medial septal area (MSA) with carbachol produces thirst, natriuresis, antidiuresis and pressor response. In the brain, hydrogen peroxide (H2O2) modulates autonomic and behavioral responses. In the present study, we investigated the effects of the combination of carbachol and H2O2 injected into the MSA on water intake, renal excretion, cardiovascular responses and the activity of vasopressinergic and oxytocinergic neurons in the hypothalamic paraventricular (PVN) and supraoptic (SON) nuclei. Furthermore, the possible modulation of carbachol responses by H2O2 acting through K-ATP(+) channels was also investigated. Male Holtzman rats (280-320 g) with stainless steel cannulas implanted in the MSA were used. The pre-treatment with H2O2 in the MSA reduced carbacholinduced thirst (7.9 +/- 1.0, vs. carbachol: 13.2 +/- 2.0 ml/60 min), antidiuresis (9.6 +/- 0.5, vs. carbachol: 7.0 +/- 0.8 ml/120 min,), natriuresis (385 +/- 36, vs. carbachol: 528 +/- 46 mu Eq/120 min) and pressor response (33 +/- 5, vs. carbachol: 47 +/- 3 mmHg). Combining H2O2 and carbachol into the MSA also reduced the number of vasopressinergic neurons expressing c-Fos in the PVN (46.4 +/- 11.2, vs. carbachol: 98.5 +/- 5.9 c-Fos/AVP cells) and oxytocinergic neurons expressing c-Fos in the PVN (38.5 +/- 16.1, vs. carbachol: 75.1 +/- 8.5 c-Fos/OT cells) and in the SON (57.8 +/- 10.2, vs. carbachol: 102.7 +/- 7.4 c-Fos/OT cells). Glibenclamide (K-ATP(+) channel blocker) into the MSA partially reversed H2O2 inhibitory responses. These results suggest that H2O2 acting through K-ATP(+) channels in the MSA attenuates responses induced by cholinergic activation in the same area. (C) 2014 IBRO. Published by Elsevier Ltd. All rights reserved. (AU)

• FAPESP's process: 11/15340-6 - Effects of hydrogen peroxide in the medial septal area on the water intake, urinary excretion and pressor response induced by cholinergic stimulation of the medial septal area
• Grantee: Mariana Del Rosso de Melo
• Support Opportunities: Scholarships in Brazil - Master