Cholinergic function of commissural nucleus of the solitary tract on cardiorespiratory responses to hypoxia, hypercapnia and pH decrease

• Grant number: 13/22526-4
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: June 01, 2014
• End date: July 31, 2017
• Field of knowledge: Biological Sciences - Physiology - Physiology of Organs and Systems
• Agreement: Coordination of Improvement of Higher Education Personnel (CAPES)
• Principal Investigator: Débora Simões de Almeida Colombari
• Grantee: Werner Issao Furuya
• Host Institution: Faculdade de Odontologia (FOAr). Universidade Estadual Paulista (UNESP). Campus de Araraquara. Araraquara , SP, Brazil
• Associated research grant: 09/54888-7 - Neural mechanisms involved on chemoreception, AP.TEM
• Associated scholarship(s): 16/02725-0 - Cholinergic mechanisms of the intermediate nucleus of the solitary tract involved in the cardiorespiratory responses of the Hering-Breuer reflex, BE.EP.DR

Abstract

The nucleus of the solitary tract (NTS) is the primary site of visceral afferents, such as baroreceptors and arterial chemoreceptors. Recent data from our laboratory have shown that the microinjection of acetylcholine (ACh) into the commissural moiety of the NTS (cNTS) of decorticated arterially-perfused in situ preparations of male juvenile rats did not change the sympathetic nerve activity (SNA), but increased the phrenic nerve activity (PNA). Furthermore, we demonstrated that the ACh-induced responses in cNTS involve the activation of both nicotinic and muscarinic receptors. However, nicotinic receptors seem to play a more relevant role in the control of breathing, especially considering that such receptor antagonism promotes a decrease in the KCN- activated peripheral chemoreflex tachypneic response. However, the effects of specific nicotinic and muscarinic agonists in the cNTS on respiratory and sympathetic responses have not been studied yet. Once established the involvement of nicotinic receptors in the cNTS on peripheral chemoreflex ventilatory responses activated by cytotoxic hypoxia (KCN), we intend to study the involvement of the cholinergic system in the cNTS on respiratory and sympathetic responses induced by hypoxic hypoxia, hypercapnia, or pH changes in the cNTS, as well as which cholinergic receptor subtypes are involved. Moreover, although the presence of a cholinergic system in the NTS has been described, the efferent projections of ACh-activated cNTS neurons, especially to medullary regions involved in the control of ventilation, has not been studied yet. Therefore, this project proposes to study, in detail, the effects of selective activation of distinct cholinergic receptors in the cNTS on respiratory and sympathetic activities, the role of the cholinergic system in cNTS on sympathetic and respiratory activities reflex changes in response to hypoxic hypoxia, hypercapnia and decrease in the cNTS pH and the efferent projections from neurons activated by ACh in the cNTS to medullary areas involved in the respiratory and sympathetic control. (AU)

Scientific publications

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

FURUYA, WERNER I.; BASSI, MIRIAN; MENANI, JOSE V.; COLOMBARI, EDUARDO; ZOCCAL, DANIEL B.; COLOMBARI, DEBORA S. A.. Modulation of hypercapnic respiratory response by cholinergic transmission in the commissural nucleus of the solitary tract. PFLUGERS ARCHIV-EUROPEAN JOURNAL OF PHYSIOLOGY, v. 472, n. 1, DEC 2019. (13/22526-4, 13/17251-6)