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This Article Full Text Full Text (PDF) All Versions of this Article: 89/6/709    most recent expphysiol.2004.028233v1 Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Thomas, C. J Articles by Woods, R. L Search for Related Content PubMed PubMed Citation Articles by Thomas, C. J Articles by Woods, R. L Related Collections Cardiovascular control

¹ Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Victoria 3010, Australia

While atrial and B-type natriuretic peptides (ANP and BNP) have been shown to enhance reflex responses attributed to cardiac vagal afferents, their effects on arterial baroreceptor reflex function remain controversial. The actions of C-type natriuretic peptide (CNP) in this regard are unknown. To clarify their actions on arterial baroreflexes, we tested whether I.V. infusions of ANP, BNP or CNP at 10 pmol kg^–1 min^–1 modified the steady-state mean arterial blood pressure–heart rate (MAP–HR) relationship in conscious sheep. At this dose, all three natriuretic peptides are known to enhance the cardiac chemoreflex response to phenylbiguanide (Bezold-Jarisch reflex). Sigmoid MAP–HR relationships were constructed from the steady-state responses to alternating injections of vasopressor (phenylephrine, 1–15 µg kg^–1) and vasodepressor agents (nitroprusside, 1–15 µg kg^–1) in the absence and presence of infused ANP, BNP or CNP (tested in random order at least 1 week apart). No parameter of the steady-state baroreflex relationship was significantly altered by infusion of any of the three natriuretic peptides. We conclude that in conscious sheep, normal arterial baroreceptor–HR reflex function prevails in the presence of moderate doses of ANP, BNP or CNP.

(Received 3 June 2004; accepted after revision 24 August 2004; first published online 13 September 2004)
Corresponding author R. L. Woods: Howard Florey Institute, University of Melbourne, Victoria 3010, Australia. Email: r.woods{at}hfi.unimelb.edu.au