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28. Wissenschaftlicher Kongress der Deutschen Hochdruckliga

24. bis 27.11.2004, Hannover

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Influence of Short-term versus Prolonged Cardiopulmonary Receptor Stimulation on Renal and Adrenal Sympathetic Nerve Activity in Rats

Kurzfristige und prolongierte Stimulation kardiopulmonaler Rezeptoren: Einfluß auf renalen und adrenalen Sympathikus

Meeting Abstract (Hypertonie 2004)

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  • T. Ditting - Dept. Nephrology J. W. Goethe-University (Frankfurt, D)
  • K.F. Hilgers - Dept. Nephrology, Friedrich-Alexander-University Erlangen, D)
  • K. Amann - Dept. Pathology, Friedrich-Alexander-University Erlangen, D)
  • R. Veelken - Dept. Pathology, Friedrich-Alexander-University Erlangen, D)

Hypertonie 2004. 28. Wissenschaftlicher Kongress der Deutschen Hochdruckliga. Hannover, 24.-27.11.2004. Düsseldorf, Köln: German Medical Science; 2005. Doc04hochP37

The electronic version of this article is the complete one and can be found online at: http://www.egms.de/en/meetings/hoch2004/04hoch037.shtml

Published: August 10, 2005

© 2005 Ditting et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

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Renal and preganglionic adrenal sympathetic nerve activity (RSNA, ASNA) are known to be regulated differentially. We investigated different modes of cardiopulmonary receptor stimulation (mechanical/chemical) to distinguish between 1) short-term and prolonged stimulus effects on sympathetic nerve activity (SNA) as well as 2) stimulus specific effects.

In rats mean arterial blood pressure (MAP), heart rate (HR), left ventricular end-diastolic pressure (LVEDP), renal and adrenal sympathetic nerve activity (RSNA, ASNA) were measured. Experiments were repeated with bilateral cervical vagotomy (Vx). Cardiopulmonary receptors were stimulated in different ways: Short-term: LVEDP changes (±4, ±6, ±8 mmHg) by aortic or caval vein obstruction, respectively; 5HT3-receptor stimulation by phenylbiguanide (PBG-boli iv); Prolonged (15 minutes): volume expansion to increase LVEDP (0.9% NaCl, 5% body weight); hemorrhage to decrease LVEDP by 50 mmHg; PBG infusion (32µg/min).

Short-term increases and decreases of LVEDP uniformly decreased SNA (RSNA -52±12%; ASNA -37±13%, n=8). PBG-bolus decreased RSNA (-54±12%) but increased ASNA (+40±13%). All reflex responses were abolished by Vx. Volume expansion decreased RSNA (-55±7%) but did not affect ASNA. PBG-infusion lead to sustained decrease in RSNA (-60±6%) but lead to non-sustained (2min) increase in ASNA (+120±15%), resembling short-term stimulus response. Again all responses were abolished by Vx. Hemorrhage decreased RSNA (-39±9%) but increased ASNA (+42±9%). RSNA response was abolished by Vx. but not ASNA.

Short-term mechanical stimulation of cardiopulmonary receptors uniformly decreased RSNA and ASNA whereas short-term chemical stimulation induced opposed responses in respective SNA. However, the major finding was that ASNA in contrast to RSNA ASNA was unaffected by prolonged stimulation of cardiopulmonary receptors independent of the stimulus mode. This points to differential central processing of afferent input.