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Basic Research in Cardiology

, Volume 77, Issue 5, pp 507–519 | Cite as

Cardiovascular reflexes controlling regional sympathetic outflow during coronary artery occlusion

  • R. Kullmann
Original Contributions

Summary

In anesthetized rabbits, sympathetic activity was recorded in efferents to the skin of the ear (ESA), to the hindlimb muscles (MSA), splanchnic region (SSA), adrenals (ASA), and kidneys (KSA) in response to occlusion of the left circumflex coronary artery. Coronary occlusion caused an average decrease of mean arterial blood pressure by 18%. MSA and SSA increased, ESA decreased, and ASA, KSA, and heart rate either decreased or increased. In response to occlusion after cervical vagotomy, the fall in arterial mean pressure (11%) and the increases in MSA and SSA were less than those with intact vagal nerves. ASA and KSA increased, ESA decreased, and heart rate did not change significantly. In response to occlusion after selective sinoaortic denervation, arterial mean pressure dropped more than before denervation (32%); heart rate fell slightly. The increases in MSA and SSA were almost completely abolished, but in some rabbits irregular bursts were observed in KSA. The results suggest that a vagal depressor reflex dominated the arterial baroreflex in the control of the sympathetic outflow to the kidneys and adrenals without apparently influencing the outflow to the other investigated regions. There are some indications that excitation of cardiac receptors with sympathetic afferents contributed to the changes of ESA and KSA.

Key words

coronary artery occlusion regional sympathetic activity sinoaortic afferents vagal afferents sympathetic afferents 

Zusammenfassung

An narkotisierten Kaninchen wurden die während Verschluß des Ramus circumflexus der linken Koronararterie auftretenden Aktivitätsänderungen im N. splanchnicus major sowie in Sympathikusefferenzen zur Haut des Ohres, zur Muskulatur der Hinterextremität, zur Nebenniere und zur Niere registriert. Die Koronarokklusion verursachte einen mittleren Blutdruckabfall um 18%. Die Aktivität in Efferenzen zur Skelettmuskulatur und im N. splanchnicus major nahm zu, die Aktivität im Ohrsympathikus fiel ab, und die Entladungsrate in Efferenzen zur Nebenniere und Niere nahm entweder ab oder zu. Wurde die Koronarokklusion nach beidseitiger Durchschneidung des Halsvagus durchgeführt, fiel der arterielle Mitteldruck geringer ab (um 11%) als unter Kontrollbedingungen; auch der Aktivitätsanstieg in den Efferenzen zur Skelettmuskulatur und im N. splanchnicus major war geringer. In den Efferenzen zur Nebenniere und Niere nahm die Entladungsrate zu, die Aktivität des Ohrsympathikus fiel ab, und die Herzfrequenz änderte sich nicht signifikant. Während Okklusion nach selektiver sinoaortaler Denervierung nahm der arterielle Mitteldruck stärker ab (um 32%) als unter Kontrollbedingungen; die Herzfrequenz fiel geringfügig ab. Der vorher nachweisbare Aktivitätsanstieg in Efferenzen zur Skelettmuskulatur und im N. splanchnicus major wurde durch die sinoaortale Denervierung fast vollständig aufgehoben; im Nierensympathikus traten jedoch bei einigen Kaninchen unregelmäßige Entladungssalven auf. Die Ergebnisse lassen vermuten, daß ein depressorischer Vagusreflex die Wirkung arterieller Barorezeptorenreflexe auf die Efferenzen im Nieren- und Nebennierensympathikus unterdrückte und dadurch deren Aktivitätsänderungen maßgeblich beeinflußte, ohne eindeutig die Aktivität in den Efferenzen zu den anderen untersuchten Organgebieten zu hemmen. Einige Hinweise sprechen dafür, daß eine Erregung kardialer Rezeptoren, deren Afferenzen im Sympathikus verlaufen, an den Aktivitätsänderungen des efferenten Ohr- und Nierensympathikus beteiligt war.

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Copyright information

© Dr. Dietrich Steinkopff Verlag 1982

Authors and Affiliations

  • R. Kullmann
    • 1
  1. 1.Institut für Pharmakologie und Toxikologie der Universität BonnBonn 1Fed. Rep. Germany

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