Neural Regulation Of The Heart Beat
Physiology
Levy M N; Martin P J
Annual Review of Physiology
1981
1981
Journal Article or Conference Abstract Publication
<a href="http://doi.org/10.1146/annurev.ph.43.030181.002303" target="_blank" rel="noreferrer noopener">10.1146/annurev.ph.43.030181.002303</a>
Effects of ionic channel antagonists barium, cesium, and UL-FS-49 on vagal slowing of atrial rate in dogs
acetylcholine; atrioventricular nodes; autonomic nervous system; block; cardiac pacemaker; Cardiovascular System & Cardiology; cat; current if; heart rate; ionic currents; pacemaker activity; parasympathetic; Physiology; purkinje-fibers; sinoatrial node cells; sinus node; stimulation; vagus nerves
In response to a brief vagal stimulus, the atrial rate initially slows, then transiently accelerates, and slows a second time. We determined the effects of three antagonists to two ionic channels on this characteristic triphasic pacemaker response. Brief bursts of vagal stimulation were delivered to anesthetized dogs, and atrial cycle lengths were recorded. Either barium, cesium, or UL-FS-49 was administered. Barium, which primarily blocks the acetylcholine-sensitive potassium current (I-K,I-ACh), attenuated the initial vagally induced bradycardia by >50% without affecting the subsequent acceleration or the secondary slowing. Cesium and UL-FS-49 [both of which primarily block the pacemaker current (I-f)] did not affect the initial vagal slowing of atrial rate but abolished the acceleratory portion of the response. The secondary slowing was abolished by cesium but not by UL-FS-49. We conclude that the initial rapid atrial response to acetylcholine is mediated mainly by the I-K,I-ACh, with little contribution from the I-f. The subsequent acceleration is mediated by activation of the I-f.
Wallick D W; Kuguoglu A; Yang T N; Stuesse S L; Levy M N
American Journal of Physiology-Heart and Circulatory Physiology
1997
1997-11
Journal Article
<a href="http://doi.org/10.1152/ajpheart.1997.273.5.h2155" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.1997.273.5.h2155</a>
EFFECTS OF GLUCAGON ON CARDIAC CHRONOTROPIC RESPONSE TO VAGAL-STIMULATION IN THE DOG
Physiology
Stuesse S L; Levy M N; Zieske H
American Journal of Physiology
1982
1982
Journal Article
<a href="http://doi.org/10.1152/ajpheart.1982.242.1.h7" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.1982.242.1.h7</a>
CHANGES IN VAGAL PHASIC CHRONOTROPIC RESPONSES WITH SYMPATHETIC-STIMULATION IN THE DOG
Physiology
Stuesse S L; Wallick D W; Zieske H; Levy M N
American Journal of Physiology
1981
1981
Journal Article
<a href="http://doi.org/10.1152/ajpheart.1981.241.6.h850" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.1981.241.6.h850</a>
AUTONOMIC CONTROL OF RIGHT ATRIAL CONTRACTILE STRENGTH IN THE DOG
Physiology
Stuesse S L; Wallick D W; Levy M N
American Journal of Physiology
1979
1979
Journal Article
<a href="http://doi.org/10.1152/ajpheart.1979.236.6.h860" target="_blank" rel="noreferrer noopener">10.1152/ajpheart.1979.236.6.h860</a>