Muscarinic cholinergic receptors modulate vagal cardiac responses in man. J Auton Nerv Syst 1983;7(3-4):271-8
Date
03/01/1983Pubmed ID
6875192DOI
10.1016/0165-1838(83)90080-2Scopus ID
2-s2.0-0020961073 (requires institutional sign-in at Scopus site) 69 CitationsAbstract
Respiratory sinus arrhythmia (peak-valley P-P interval changes during controlled breathing) and carotid baroreceptor-cardiac reflex responses (provoked by neck suction) were studied before and after low (0.725 microgram/kg) or high (0.043 mg/kg) dose atropine sulfate infusions in 22 healthy young adults. There was a highly significant (r = 0.78, P = 0.002) correlation between resting respiratory sinus arrhythmia and baroreflex responses. Low dose atropine increased the magnitude of sinus arrhythmia and baroreflex responses. Large dose atropine reduced sinus arrhythmia and baroreflex responses in an exponential fashion. Our results link respiratory sinus arrhythmia with baroreflex responsiveness and provide inferential evidence that vagal cardiac efferent activity is modulated by inhibitory cholinergic receptors. We speculate that blockade of these receptors by low doses of atropine amplifies vagal motoneuron responses to incoming baroreceptor information, and thereby increases average maximum and minimum levels of vagal cardiac outflow during breathing.
Author List
Raczkowska M, Eckberg DL, Ebert TJAuthor
Thomas J. Ebert MD, PhD Adjunct Professor in the Anesthesiology department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
AdultAtropine
Blood Pressure
Dose-Response Relationship, Drug
Efferent Pathways
Female
Heart
Heart Rate
Humans
Male
Motor Neurons
Pressoreceptors
Receptors, Cholinergic
Receptors, Muscarinic
Reflex
Respiration
Vagus Nerve
