Baroreceptor-mediated activation of sympathetic nerve activity to salivary glands

Author(s)

Sabino-Silva, Robinson ^[1] ; Ceroni, Alexandre ^[1] ; Koganezawa, Tadachika ^[2] ; Michelini, Lisete C. ^[1] ; Machado, Ubiratan F. ^[1] ; Antunes, Vagner R. ^[1]

Affiliation

^[1] Univ Sao Paulo, Inst Biomed Sci, Dept Physiol & Biophys, BR-05505900 Sao Paulo - Brazil

^[2] Univ Tsukuba, Grad Sch Comprehens Human Sci, Inst Basic Med Sci, Dept Physiol, Tsukuba, Ibaraki 305 - Japan

• Document type: Journal article
• Source: Physiology & Behavior; v. 107, n. 3, p. 390-396, OCT 10 2012.
• Web of Science Citations: 0

Abstract

Salivary gland function is regulated by both the sympathetic and parasympathetic nervous systems. Previously we showed that the basal sympathetic outflow to the salivary glands (SNA(SG)) was higher in hypertensive compared to normotensive rats and that diabetes reduced SNA(SG) discharge at both strains. In the present study we sought to investigate how SNA(SG) might be modulated by acute changes in the arterial pressure and whether baroreceptors play a functional role upon this modulation. To this end, we measured blood pressure and SNA(SG) discharge in Wistar-Kyoto rats (WRY-intact) and in WRY submitted to sinoaortic denervation (WRY-SAD). We made the following three major observations: (i) in WRY-intact rats, baroreceptor loading in response to intravenous infusion of the phenylephrine evoked an increase in SNA(SG) spike frequency (81%, p<0.01) accompanying the increase mean arterial pressure ((sic)MAP: +77 +/- 14 mmHg); (ii) baroreceptor unloading with sodium nitroprusside infusion elicited a decrease in SNA(SG) spike frequency (17%, p<0.01) in parallel with the fall in arterial blood pressure ((sic)MAP: 30 3 mmHg) in WRY-intact rats; iii) in the WRY-SAD rats, phenylephrine-evoked rises in the arterial pressure ((sic)MAP: +56 +/- 6 mmHg) failed to produce significant changes in the SNA(SG) spike frequency. Taken together, these data show that SNA(SG) increases in parallel with pharmacological-induced pressor response in a baroreceptor dependent way in anaesthetised rats. Considering the key role of SNA(SG) in salivary secretion, this mechanism, which differs from the classic cardiac baroreflex feedback loop, strongly suggests that baroreceptor signalling plays a decisive role in the regulation of salivary gland function. (C) 2012 Elsevier Inc. All rights reserved. (AU)

• FAPESP's process: 07/50554-1 - Glucose transporters and diabetes mellitus: contribution to the knowledge of glycemic control and chronic diseases development
• Grantee: Ubiratan Fabres Machado
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 07/04085-0 - Functional analysis of genes contributing to neurogenic hypertension
• Grantee: Vagner Roberto Antunes
• Support Opportunities: Regular Research Grants
• FAPESP's process: 09/16502-0 - Characterization of central nuclei involved in sympathetic activity modulation to salivary glands: control of salivary glucose concentration and flux in hypertensive and diabetic rats.
• Grantee: Robinson Sabino da Silva
• Support Opportunities: Scholarships in Brazil - Post-Doctoral