scholarly journals Transthoracic cardiac ultrasonic stimulation induces a negative chronotropic effect

2012 ◽  
Vol 59 (12) ◽  
Author(s):  
E. B. Buiochi ◽  
R. J. Miller ◽  
E. Hartman ◽  
F. Buiochi ◽  
R. A. Bassani ◽  
...  
Keyword(s):  
Chronotropic Effect ◽  
Negative Chronotropic Effect ◽  
Ultrasonic Stimulation

scholarly journals Electrophysiological analysis of the negative chronotropic effect of endothelin‐1 in rabbit sinoatrial node cells

2001 ◽  
Vol 537 (2) ◽  
pp. 467-488 ◽  
Author(s):  
Kageyoshi Ono ◽  
Haruko Masumiya ◽  
Aiji Sakamoto ◽  
Georges Christé ◽  
Toshinori Shijuku ◽  
...  
Keyword(s):  
Sinoatrial Node ◽  
Chronotropic Effect ◽  
Endothelin 1 ◽  
Negative Chronotropic Effect ◽  
Electrophysiological Analysis ◽  
Sinoatrial Node Cells ◽  
Rabbit Sinoatrial Node

Inhibitory effects of catecholamines in canine cardiac Purkinje fibers

1976 ◽  
Vol 231 (5) ◽  
pp. 1415-1420 ◽  
Author(s):  
P Posner ◽  
EL Farrar ◽  
CR Lambert
Keyword(s):  
Negative Response ◽  
Chronotropic Effect ◽  
Inhibitory Effects ◽  
Purkinje Fibers ◽  
Spontaneous Rate ◽  
Negative Chronotropic Effect ◽  
Cardiac Purkinje Fibers ◽  
Wide Range ◽  
Low Levels

The effect of catecholamines over a wide range of concentrations was studied on 42K uptake and efflux, as well as on spontaneous rate in canine cardiac Purkinje fibers. Low levels of catecholamines (less than 10(-10) M epinephrine; less than 10(-9) M norepinephrine) decreased automaticity. This negative chronotropic effect was blocked by phentolamine and mimicked by phenylephrine. These low levels of epinephrine and norepinephrine also inhibited 42K uptake by Purkinje fibers but had no effect on 42K efflux. The inhibition of 42K uptake was blocked by phentolamine and verapamil and mimicked by phenylephrine. The data indicate an alpha-receptor-mediated negative response of rate and 42K uptake to low levels of catecholamine. The end result is discussed in terms of a competitive increase in the influx of Ca2+ rather than Na+ and an indirect inhibition of the Na+-K+ pump.

scholarly journals Heart reaction of male and female with streptozotocin induced diabetes on cholinergic impacts

2020 ◽  
Vol 73 (2) ◽  
pp. 224-228
Author(s):  
Orysia O. Bandrivska ◽  
Vitalij M. Mykhailiuk ◽  
Iryna A. Mykhailiuk ◽  
Natalia V. Malko
Keyword(s):  
Vagus Nerve ◽  
Sinus Node ◽  
Female Rats ◽  
Chronotropic Effect ◽  
Maximum Increase ◽  
Male And Female ◽  
Negative Chronotropic Effect ◽  
Male And Female Rats ◽  
Streptozotocin Induced Diabetes ◽  
Stimulation Of

The aim: Find out the nature of the changes sensitivity of the heart to the cholinergic influences the development of diabetes depending on gender. Materials and methods: In experiments on adult male and female rats, type 1 diabetes by momentary introduction of streptozotocin at a dose of 60 mg/ kg into the peritoneal cavity was modeled. Animals were examined after 15, 30, 60 and 90 days after introduction of streptozotocin. We studied the sensitivity of cholinoreceptors of sinus node by the intensity of bradycardia with intravenous injection of acetylcholine and electrical stimulation of the peripheral segment of the right vagus nerve. Results: It was established that the intensity of the negative chronotropic effect of heart of males by electric stimulation of the vagus nerve, which depends on the reserves of acetylcholine in the presynaptic section and sensitivity of postsynaptic cholinoreceptors, increased gradually and after 90 days prevailed the output value in 2.2 times. This occurred at the background of a slight (10 %) decrease in response to exogenous acetylcholine that reflected the decrease in sensitivity of cholinoreceptors. In females the maximum increase (in 4.4 times) of the intensity of the negative chronotropic effect of vagus nerve stimulation was observed after 30 days from the start of the experiment. After 90 days, this indicator prevailed the controlled one in 3.3 times, which occurred at the background of heart response decreasing to exogenous acetylcholine (in 1.7 times). Conclusions: Obtained results suggest a more significant change in state of cholinoceptor system of myocardium of females compared with males in the dynamics of development of streptozotocin-induced diabetes.

Absence of direct chronotropic action of angiotensin infused into the sinus node artery

1965 ◽  
Vol 209 (3) ◽  
pp. 571-576 ◽  
Author(s):  
Thomas N. James
Keyword(s):  
Sinus Tachycardia ◽  
Sinus Node ◽  
Systemic Effect ◽  
Chronotropic Effect ◽  
Sinus Node Artery ◽  
Negative Chronotropic Effect ◽  
Chronotropic Action ◽  
Vagal Reflex

Angiotensin was shown to have no significant direct chronotropic action when perfused into the canine sinus node through its artery in situ. A slight cardiac acceleration which occurs during the systemic effect (aortic hyper-tension) from angiotensin is not due to sensitization of the sinus node to norepinephrine. Since it can be reversed and blocked with naphthylisoproterenol, this sinus tachycardia is presumably mediated by catecholamines delivered to the heart from an extracardiac source. Slowing of the sinus node during hypertension from angiotensin in the nonatropinized dog is due to a vagal reflex and is not caused by a direct negative chronotropic effect on the sinus node.

Possible involvement of nitric oxide-cGMP pathway in the negative chronotropic effect of CD-832, a novel dihydropyridine derivative

Life Sciences ◽  
1998 ◽  
Vol 62 (10) ◽  
pp. 897-903
Author(s):  
K. Noguchi ◽  
T. Shijuku ◽  
C. Nakasone ◽  
K. Takahashi ◽  
S. Higuchi ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
Chronotropic Effect ◽  
Negative Chronotropic Effect ◽  
Cgmp Pathway ◽  
Dihydropyridine Derivative

Desensitization to acetylcholine in single sinoatrial node cells isolated from rabbit hearts

1992 ◽  
Vol 263 (6) ◽  
pp. H1779-H1789 ◽  
Author(s):  
H. Honjo ◽  
I. Kodama ◽  
W. J. Zang ◽  
M. R. Boyett
Keyword(s):  
Potassium Current ◽  
Sinoatrial Node ◽  
Chronotropic Effect ◽  
Patch Clamp Technique ◽  
Membrane Hyperpolarization ◽  
Chronotropic Response ◽  
Negative Chronotropic Effect ◽  
Whole Cell Patch Clamp ◽  
Sinoatrial Node Cells ◽  
Continuous Presence

The negative chronotropic effect of acetylcholine (ACh) on the sinoatrial node fades in the continuous presence of ACh as a result of desensitization. We have investigated the mechanism underlying desensitization in single rabbit sinoatrial node cells using the whole cell patch clamp technique. The negative chronotropic effect resulting from the injection of a constant hyperpolarizing current faded. ACh activated an inwardly rectifying potassium current (iK,ACh), which faded in the continuous presence of ACh. ACh had no effect on “basal” L-type calcium current (iCa), but ACh decreased iCa, which had been potentiated by isoprenaline. This effect did not fade during a 2-min exposure to ACh. ACh decreased the hyperpolarization-activated current (i(f)). This effect again did not fade. These results suggest that desensitization of the negative chronotropic response to ACh is, in part, the result of the membrane hyperpolarization and, in part, the result of the fade of iK,ACh. These results also suggest that, whereas the activation of potassium current by ACh rapidly fades, the effects resulting from the inhibition of adenylate cyclase do not.

NEGATIVE CHRONOTROPIC EFFECT AND ANGINA DUE TO THALIDOMIDE USE

2019 ◽  
Vol 73 (9) ◽  
pp. 2923 ◽  
Author(s):  
Luis Olmos Dominguez ◽  
Milton Ernesto Guevara Valdivia ◽  
Jose Oscar Torres Jaimes ◽  
Karim Yarek Juarez Escobar ◽  
Yitzar Bañuelos Millan ◽  
...  
Keyword(s):  
Chronotropic Effect ◽  
Negative Chronotropic Effect
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