The Role of Propranolol’s Negative Chronotropic Effect on Protection of the Ischemic Myocardium

Pharmacology ◽  
1979 ◽  
Vol 19 (4) ◽  
pp. 202-208 ◽  
Author(s):  
David Hillis ◽  
Shukri F. Khun ◽  
Eugene Braunwald ◽  
Peter R. Maroko
Keyword(s):  
Ischemic Myocardium ◽  
Chronotropic Effect ◽  
Negative Chronotropic Effect

scholarly journals ROLE OF MEDICATIONS WITH NEGATIVE CHRONOTROPIC EFFECT IN THE TREATMENT OF PATIENTS WITH CORONARY HEART DISEASE AND HEART FAILURE

2013 ◽  
Vol 12 (5) ◽  
pp. 81-86
Author(s):  
M. G. Glezer ◽  
E. I. Astashkin ◽  
I. N. Sokolova
Keyword(s):  
Heart Failure ◽  
Coronary Heart Disease ◽  
Heart Disease ◽  
Combination Therapy ◽  
Clinical Course ◽  
Dose Titration ◽  
Chronotropic Effect ◽  
Negative Chronotropic Effect

The study aim was to assess the importance of adequate administration of medications with negative chronotropic effect in the improvement of clinical course and prognosis among patients with coronary heart disease (CHD) and heart failure. The possibility and appropriateness of combination therapy with β-adrenoblockers (β-AB) and an If channel blocker ivabradine is justified. The authors analyse current real-world trends in the administration and dose titration of these medications among ambulatory Russian patients. Russian doctors need to be more active in the treatment of patients with CHD and heart failure and better understand the need for and benefits of dose titration of medications with negative chronotropic effect, as well as the importance of combination therapy for the improvement of clinical course, prognosis, and quality of life. 

Electrophysiological-anatomic correlates of ATP-triggered vagal reflex in the dog. V. Role of purinergic receptors

2005 ◽  
Vol 288 (3) ◽  
pp. R651-R655 ◽  
Author(s):  
Jiang Xu ◽  
William Kussmaul ◽  
Peter B. Kurnik ◽  
Mohamad Al-Ahdav ◽  
Amir Pelleg
Keyword(s):  
Coronary Artery ◽  
Purinergic Receptor ◽  
Sinus Node ◽  
Sensory Nerve ◽  
Extracellular Atp ◽  
Left Ventricular ◽  
Chronotropic Effect ◽  
Negative Chronotropic Effect ◽  
Depressor Reflex

The mechanism of extracellular ATP-triggered vagal depressor reflex was further studied in a closed-chest canine model. Adenosine and ATP were administered individually in equimolar doses (0.01–1.0 μmol/kg) into the right coronary artery (RCA) and left circumflex coronary artery (LCA). When administered into the RCA, adenosine and ATP exerted an identical and relatively small negative chronotropic effect on sinus node automaticity; the time to peak negative chronotropic effect was ≥7 s. When administered into the LCA, adenosine had no effect on sinus node automaticity, whereas ATP markedly suppressed sinus node automaticity. This effect of ATP 1) reached its peak in <2 s after its administration, 2) was short lasting, and 3) was completely abolished by either intravenous administration of the muscarinic cholinergic blocker atropine (0.2 mg/kg) or intra-LCA administration of 2′,3′- O-(2,4,6 -trinitrophenyl)-ATP (TNP-ATP), a potent P2X2/3 purinergic receptor (P2X2/3R) antagonist, but not by diinosine pentaphosphate (Ip5I), a potent inhibitor of P2X1R and P2X3R. Repetitive administrations of ATP were not associated with reduced effects, indicative of receptor desensitization, thereby excluding the involvement of the rapidly desensitized P2X1R in the action of ATP. It was concluded that ATP triggers a cardio-cardiac vagal depressor reflex by activating P2X2/3R located on vagal sensory nerve terminals localized in the left ventricle. Because these terminals mediate vasovagal syncope, these data could suggest a mechanistic role of extracellular ATP in this syndrome and, in addition, give further support to the hypothesis that endogenous ATP released from ischemic myocytes is a mediator of atropine-sensitive bradyarrhythmias associated with left ventricular myocardial infarction.

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

Role of phospholipases A2 and C in myocardial ischemic reperfusion injury

1991 ◽  
Vol 260 (3) ◽  
pp. H877-H883 ◽  
Author(s):  
M. R. Prasad ◽  
L. M. Popescu ◽  
I. I. Moraru ◽  
X. K. Liu ◽  
S. Maity ◽  
...  
Keyword(s):  
Immunoglobulin G ◽  
Ischemic Myocardium ◽  
Lower Amount ◽  
Cellular Injury ◽  
Membrane Phospholipids ◽  
Nonesterified Fatty Acids ◽  
Subcellular Organelles ◽  
Phospholipases A2 ◽  
Rat Hearts

We investigated the role of phospholipase A2 (PLA2) and phospholipase C (PLC) in myocardial phosholipid degradation and cellular injury during reperfusion of ischemic myocardium. For this purpose, isolated rat hearts were perfused with isotopic arachidonic acid to label its membrane phospholipids. Hearts preperfused with antiphospholipase A2 (anti-PLA2) retained a significantly higher amount of radiolabel in phosphatidylcholine and phosphatidylinositol and a corresponding lower amount of radiolabel in lysophosphatidylcholine and nonesterified fatty acids (P less than 0.05) after 30 min of reperfusion following 30 min of normothermic global ischemia compared with hearts preperfused with nonimmune immunoglobulin G. In similar experiments, antiphospholipase C (anti-PLC)-treated hearts were associated with significantly (P less than 0.05) higher radiolabel in all phospholipids and lower radiolabel in diacyglycerol compared with nonimmune immunoglobulin G-treated hearts. Measurement of phospholipase activity in subcellular organelles of these hearts showed decreased PLA2 activity in cytosol, mitochondria, and microsomes of anti-PLA2-treated hearts and decreased PLC activity of microsomes in anti-PLC-treated hearts. Furthermore, both the antiphospholipases attenuated the release of creatine kinase and lactate dehydrogenase into perfusate and increased contractility as well as coronary flow in the reperfused hearts. Results of this study suggest that both PLA2 and PLC are involved in the degradation of phospholipids and cellular injury that occur during reperfusion of ischemic myocardium.

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.

Sign in / Sign up

Export Citation Format

Share Document