Reflex cardiovascular effects of intracoronary acetylstrophanthidin in the conscious dog

1985 ◽  
Vol 248 (6) ◽  
pp. H930-H936
Author(s):  
K. W. Barron ◽  
V. S. Bishop
Keyword(s):  
Receptor Antagonist ◽  
Adrenergic Receptor ◽  
Cardiovascular Effects ◽  
Left Ventricular ◽  
Vagal Afferents ◽  
Circumflex Coronary Artery ◽  
Inotropic Effects ◽  
Conscious Dog ◽  
Intracoronary Administration ◽  
Positive Inotropic Effects

The present experiments were designed to examine the reflex cardiovascular effects of intracoronary administration of acetylstrophanthidin in the conscious dog. Administration of 4 micrograms/kg of this agent into the left circumflex coronary artery increased left ventricular dP/dtmax but had no effect on mean arterial pressure, heart rate, renal resistance, or iliac resistance. The positive inotropic effects of acetylstrophanthidin were less under control conditions (+599 mmHg/s) than during bilateral cervical vagal cold block (+850 mmHg/s, P less than 0.05); however, interruption of vagal efferent influences (atropine) alone did not alter the contractile effects of acetylstrophanthidin. Interruption of sympathetic efferent influences on the heart with either the nicotinic ganglionic receptor antagonist, hexamethonium, or the beta 1-adrenergic receptor antagonist, metoprolol, also augmented the inotropic effects of acetylstrophanthidin to a degree similar to that observed with vagal cold block. In contrast to the effects observed with acetylstrophanthidin, the inotropic effects of intracoronary administration of calcium gluconate were not altered by vagal cold block or any other conditions examined in this study. We conclude that interruption of vagal afferents results in an augmentation of the positive inotropic actions of acetylstrophanthidin and that this augmented inotropic effect can be accounted for by interruption of cardiac vagal afferent-mediated restraint on sympathetic outflow to the heart.

Reflex cardiovascular changes with veratridine in the conscious dog

1982 ◽  
Vol 242 (5) ◽  
pp. H810-H817 ◽  
Author(s):  
K. W. Barron ◽  
V. S. Bishop
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Left Ventricular Pressure ◽  
Peripheral Circulation ◽  
Left Ventricular ◽  
Vagal Afferents ◽  
Inotropic Response ◽  
Inotropic Effects ◽  
Conscious Dog ◽  
Renal Vascular

The present study was undertaken to examine the reflex responses of activation of cardiac sensory receptors in the conscious dog. Intracoronary (left circumflex coronary artery) injection of veratridine (0.10 micrograms/kg) reduced mean arterial pressure (-40 mmHg, P less than 0.05), heart rate (-34 beats/min, P less than 0.05), and maximum rate of rise of left ventricular pressure (LV dP/dtmax) (-419 mmHg/s, P less than 0.05). Bilateral cervical vagal cold block (BVB) eliminated the depressor and bradycardic responses of veratridine. BVB not only eliminated the negative inotropic response to veratridine but reversed it to a positive inotropic response (LV dP/dtmax increased 313 +/- 76 mmHg/s). Ganglionic blockade abolished all effects of veratridine. The bradycardia and negative inotropic effects caused by veratridine were attenuated by either atropine or metoprolol and completely eliminated by the combination of the two antagonists. Veratridine also produced a decrease in renal artery blood flow but had no effect on renal vascular resistance. In contrast, iliac blood flow was increased with veratridine, and this, combined with the depressor effect, resulted in a decrease in iliac vascular resistance (-37%), P less than 0.05). BVB abolished the changes in renal and iliac blood flow or resistance caused by veratridine. The results indicate that activation of cardiac receptors in the conscious dog elicits inhibitory reflexes to the heart and peripheral circulation that are mediated by vagal afferents. After vagotomy, veratridine elicited a reflex positive inotropic response, which may have resulted from activation of cardiac sympathetic afferent fibers.

Interaction of Isoflurane and Sevoflurane with α- and β-adrenoceptor Stimulations in Rat Myocardium 

1998 ◽  
Vol 88 (5) ◽  
pp. 1249-1258 ◽  
Author(s):  
Jean-Luc Hanouz ◽  
Pierre-Yves Gueugniaud ◽  
Yves Lecarpentier ◽  
Pierre Coriat ◽  
Bruno Riou
Keyword(s):  
Positive Inotropic Effect ◽  
Left Ventricular ◽  
Control Groups ◽  
Inotropic Effects ◽  
Beta Adrenoceptor ◽  
Calcium Stimulation ◽  
Positive Inotropic Effects ◽  
Inotropic Responses ◽  
Negative Inotropic Effects

Background Halothane potentiates the positive inotropic effects of alpha- and beta-adrenoceptor stimulations but impairs the positive lusitropic effect of beta-adrenoceptor stimulations. However, the interactions of isoflurane and sevoflurane with alpha- and beta-adrenoceptor stimulation have not been entirely defined. Methods The effects of 1 minimum alveolar concentration isoflurane and sevoflurane on the inotropic responses induced by phenylephrine (10(-8) to 10(-4) M) or isoproterenol (10(-8 to 10(-4) M) were studied in rat left ventricular papillary muscles in vitro (Krebs-Henseleit solution, 29 degrees C; pH, 7.4; 0.5 mM calcium; stimulation frequency, 12 pulses/min). The positive lusitropic effects of alpha- and beta-adrenoceptor stimulations were studied under isotonic and isometric conditions. Data are mean percentages of baseline +/- SEM. Results In control groups, phenylephrine (134 +/- 8%; P < 0.05) and isoproterenol (171 +/- 7%; P < 0.05) induced a positive inotropic effect. Isoflurane enhanced the positive inotropic effects of phenylephrine (185 +/- 10%; P < 0.05) and of isoproterenol (203 +/- 11%; P < 0.05). Sevoflurane enhanced the positive inotropic effects of phenylephrine (187 +/- 10%; P < 0.05) and of isoproterenol (228 +/- 11%; P < 0.05). These potentiations were similar to those previously reported with halothane. Isoflurane and sevoflurane did not modify the positive lusitropic effects under low and high loads of isoproterenol. Conclusion Although isoflurane and sevoflurane have moderate negative inotropic effects, they potentiated the positive inotropic effects of alpha- and beta-adrenoceptor stimulations but did not modify the positive lusitropic effects of beta-adrenoceptor stimulation.

Interaction of Halogenated Anesthetics with α- and β-Adrenoceptor Stimulations in Diabetic Rat Myocardium

2004 ◽  
Vol 101 (5) ◽  
pp. 1145-1152 ◽  
Author(s):  
Julien Amour ◽  
Jean-Stéphane David ◽  
Benoît Vivien ◽  
Pierre Coriat ◽  
Bruno Riou
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Positive Inotropic Effect ◽  
Diabetic Rats ◽  
Left Ventricular ◽  
Inotropic Effect ◽  
Diabetic Rat ◽  
Inotropic Effects ◽  
Beta Adrenoceptor ◽  
Alpha Adrenoceptor ◽  
Positive Inotropic Effects

Background Halogenated anesthetics potentiate the positive inotropic effects of alpha- and beta-adrenoceptor stimulations. Although diabetes mellitus induces significant myocardial abnormalities, the interaction of halogenated anesthetics and adrenoceptor stimulation in diabetic myocardium remains unknown. Methods Left ventricular papillary muscles were provided from healthy and streptozotocin-induced diabetic rats. Effects of 1 minimum alveolar concentration halothane, isoflurane, and sevoflurane on the inotropic and lusitropic responses of alpha (phenylephrine)- and beta (isoproterenol)-adrenoceptor stimulations were studied at 29 degrees C with 12 pulses/min. Data shown are mean percentage of baseline active force +/- SD. Results Phenylephrine induced comparable positive inotropic effects in healthy and diabetic rats (143 +/- 8 vs. 136 +/- 18%; not significant), but the potentiation by halogenated anesthetics was abolished in the diabetic rats (121 +/- 20, 130 +/- 20, and 123 +/- 20% for halothane, isoflurane, and sevoflurane, respectively; not significant). In diabetic rats, the positive inotropic effect of isoproterenol was markedly diminished (109 +/- 9 vs. 190 +/- 18%; P < 0.05), but its potentiation was preserved with isoflurane (148 +/- 21%; P < 0.05) and sevoflurane (161 +/- 40%; P < 0.05) but not with halothane (126 +/- 16%; not significant). Halothane induced a deleterious effect on the sarcoplasmic reticulum, as shown by its impairment in the lusitropic effect of isoproterenol, compared with isoflurane and sevoflurane. Conclusion Potentiation of the positive inotropic effect of alpha-adrenoceptor stimulation by halogenated anesthetics is abolished in diabetic rats. In contrast, potentiation of beta-adrenoceptor stimulation is preserved with isoflurane and sevoflurane but not with halothane, probably because of its deleterious effects on sarcoplasmic reticulum.

Abstract 13171: Cellular Basis of Angiotensin-(1-7) Produced Augmentation on Left Ventricular Contractile Function in Heart Failure

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Xiaowei Zhang ◽  
Heng-Jie Cheng ◽  
Peng Zhou ◽  
Tiankai Li ◽  
Wei-Min Li ◽  
...  
Keyword(s):  
Heart Failure ◽  
Enzyme Inhibitor ◽  
Contractile Function ◽  
Heart Diseases ◽  
Cardiovascular Effects ◽  
Fold Increase ◽  
Left Ventricular ◽  
Inotropic Effects ◽  
Cardiac Depression ◽  
Hoe 140

Background: Accumulating evidence suggests that Angiotensin (A)-(1-7) exhibits cardiovascular effects that are in opposition to that of AII, thus providing protection against heart diseases. However, the exact means by which A-(1-7) affords cardioprotection are unclear. Its direct cardiac effect is not well understood. We previously showed that in heart failure (HF), AII decreases left ventricle (LV) contractility. Whether A-(1-7) may antagonize AII-induced cardiac depression, thereby contributing to its beneficial actions in HF remains to be determined. We assessed the hypothesis that A-(1-7) may produce positive modulation on [Ca 2+ ] i regulation and LV and myocyte contraction via A-(1-7) receptors, coupled with nitric oxide (NO)/bradykinin (BK)-mediated mechanism. Methods: We measured LV contractility changes after A-(1-7) (650 ng/kg, iv), which produced a 20-fold increase in plasma A-(1-7) levels, mimicking the elevations caused by angiotensin-converting enzyme inhibitor therapy in HF, and compared myocyte contractile, [Ca 2+ ] i transient ([Ca 2+ ] iT ) and I Ca,L responses to A-(1-7) (10 -5 M) in 14 rats with isoproterenol induced HF (3 months after 170 mg/kg sq for 2 days). In the subsets of cell contractile study, myocytes were pretreated to inhibit NO synthase (L-NAME, 10 -5 M), BK (HOE 140, 10 -6 M) or A-(1-7) receptor [D-Ala 7 ]-A-(1-7), 10 -5 M) followed with A-(1-7) exposure. Results: Compared with baseline, after A-(1-7), E ES (47%, 1.0 vs 0.68 mmHg/μl) and M SW (49%, 94.3 vs 62.8 mmHg) were increased, indicating enhanced LV contractility. In HF myocytes, A-(1-7) increased myocyte percent shortening (28%, 6.8% vs 5.3%), the velocity of contraction (31%, 106.4 vs 74.5 μm/sec) and relengthening (41%, 74.7vs 50.1 μm/sec) accompanied by significantly-increased [Ca 2+ ] iT (27%, 0.19 vs 0.15 pA/pF) and I Ca,L (24%, 6.3 vs 5.1pA/pF). L-NAME increased, HOE 140 decreased, and A-(1-7) receptor blockade prevented myocyte contractile responses to A-(1-7). Conclusion: In HF, clinically-relevant concentrations of A-(1-7) counteracted AII-induced cardiac depression, increased [Ca 2+ ] iT and I Ca,L , and produced positive inotropic effects in both LV and myocytes. These effects are coupled with A-(1-7) receptors and involve activation of NO/BK pathways.

Abstract P500: Naltrindole And Naltrindole Derivatives Exhibit Potent Cardioprotection In Myocardial Ischemia Reperfusion Injury

2021 ◽  
Vol 129 (Suppl_1) ◽  
Author(s):  
Sunit Singh ◽  
Alexis Verwoert ◽  
Michael Bamimore ◽  
Arjun Nair ◽  
Tameka Dean ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Infarct Size ◽  
Receptor Antagonist ◽  
Opioid Receptor ◽  
Ischemia Reperfusion ◽  
Left Ventricular ◽  
Kappa Opioid Receptor ◽  
Opioid Antagonist ◽  
Inotropic Effects ◽  
Kappa Receptor

Previously, naltrindole (NTI; selective delta opioid receptor antagonist) was shown to improve post-reperfused cardiac function and reduced infarct size when given prior to ischemia (I)/ reperfusion (R) in ex-vivo rat hearts. Conversely, naloxone (NX, broad-spectrum opioid antagonist) and nor-binaltrophine (BNI, selective kappa receptor antagonist) were similar to control hearts. In this study, the effects of NTI derivatives naltriben (NTB, delta receptor antagonist) and guanidonaltrindole (GNTI, kappa receptor antagonist) were compared to NTI, BNI, and NX. Isolated hearts from male SD rats (300g) were subjected to global I(30min)/R(45min). Treatments were given 5 min before I (preconditioning) and during the first 5 min of R. Left ventricular (LV) cardiac function was measured using a pressure transducer. At the end of reperfusion, infarcted heart tissue was compared to total tissue weight. Data were evaluated using ANOVA. As shown in Table 1, NTI, NTB, and GNTI significantly improved post-reperfused cardiac function and reduced infarct size compared to control hearts. NTI and NTB elicited direct effects on cardiac function when given during preconditioning in contrast to all other study groups and were the most robust at reducing infarct size and restoring post reperfusion cardiac function. The negative inotropic effects of NTI and NTB were correlated with a decrease in the rise of ischemic pressure. GNTI also elicited significant improvement in post-reperfused cardiac function and reduction of infarct size compared to BNI which suggests a separate cardioprotective mechanism that this NTI derivative may exert in contrast to kappa opioid receptor inhibition. Results suggest that NTI and derivatives, GNTI and NTB, are cardioprotective against I/R injury resulting in reduced ischemic peak pressure (NTI/NTB) and infarct size. In future studies, we will examine the mechanism of the protective effects of NTI and derivatives in hearts subjected to I/R injury.

Abstract 902: A Beta-2 Adrenergic Receptor Polymorphism Is Associated With Increased Left Ventricular Remodeling Following First ST-Elevation Myocardial Infarction

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Rhondalyn C McLean ◽  
Glenn A Hirsch ◽  
Gary Gerstenblith ◽  
Steven P Schulman
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Receptor Antagonist ◽  
Adrenergic Receptor ◽  
Left Ventricular ◽  
Regression Analyses ◽  
Lv Remodeling ◽  
St Elevation ◽  
Lv Volumes ◽  
Receptor Polymorphism

Background: Prior studies demonstrate an association between specific β-adrenergic receptor polymorphisms and clinical outcomes in patients with chronic heart failure and following an acute coronary syndrome. The mechanism may relate to an effect on left ventricular (LV) remodeling. We hypothesized that β-adrenergic receptor polymorphisms predict LV remodeling after acute ST elevation myocardial infarction (STEMI). Methods: We assessed the presence of β-1 and β-2 adrenergic receptor polymorphisms in 122 patients after their first STEMI enrolled in a single-center randomized, double-blind placebo controlled trial of L-arginine vs. placebo, 91% of whom received successful early reperfusion therapy. All patients were treated with a beta-1 receptor antagonist and underwent baseline (mean 5.9 days following STEMI) and 6-month LV volume evaluation using gated blood pool imaging. Univariate and multivariate linear and logistic regressions were used to assess the relationships between the polymorphisms, β1 Arg389Gly, β1 Ser49Gly, β2 Gly16Arg and β2 Gly27Glu and the six-month changes in LV volumes. The top quintiles of LV end-systolic (ESV) and end-diastolic (EDV) 6-month volume increases and LV ejection fraction decrease were compared to the lower quintiles in the logistic regression analyses. Results: The polymorphisms β1 Arg389Gly, β1 Ser49Gly, β2 Gly16Arg were not associated LV remodeling. However, the 25% of patients homozygous for the β2 Glu27 variant were 5.2 times more likely to have an increase in 6-month ESV than those who had the Gln27 variant (OR 5.2, 95%CI 1.4 –19.0). Multiple linear regression analyses demonstrated that absolute ESV at six months was 19 ml greater (p = 0.02) and EDV was 21 ml greater (p = 0.01) in post STEMI patients with the β2 Glu27 polymorphism compared to the wild type or heterozygous patients. Conclusions: Increased LV volumes post-STEMI are associated with an increased risk of heart failure and death. The common β2 receptor polymorphism, Glu27Glu, is associated with increased odds of adverse LV remodeling in patients treated with a beta-one receptor antagonist. Whether treatment with a non-specific β-adrenergic receptor blocker guided by this genetic polymorphism ameliorates the effect requires further study.

Triiodothyronine Increases Contractility Independent of β-Adrenergic Receptors or Stimulation of Cyclic-3',5'-Adenosine Monophosphate

1995 ◽  
Vol 82 (4) ◽  
pp. 1004-1012. ◽  
Author(s):  
Douglas G. Ririe ◽  
John F. IV Butterworth ◽  
Roger L. Royster ◽  
Drew A. MacGregor ◽  
Gary P. Zaloga
Keyword(s):  
Thyroid Hormones ◽  
Adrenergic Receptors ◽  
Adrenergic Receptor ◽  
Adenosine Monophosphate ◽  
Left Ventricular ◽  
Camp Production ◽  
Beta Adrenergic Receptor ◽  
Beta Adrenergic ◽  
Inotropic Effects ◽  
Isolated Rat

Background Triiodothyronine regulates cardiac contractility; however, the mechanisms by which it produces its acute contractile effects remains unknown. We compared the acute effects of thyroid hormones (triiodothyronine [T3] and thyroxine [T4]) and of isoproterenol on the contractility of isolated rat hearts. In addition, we sought to determine whether the acute inotropic effects of thyroid hormones were mediated by beta-adrenergic receptors or by increased production of cyclic-3',5'-adenosine monophosphate (cAMP). Methods A Langendorff heart preparation harvested from euthyroid male Sprague-Dawley rats was used. Drugs were administered through an aortic perfusion catheter. A pressure-transduced left-ventricular balloon catheter measured pressure and heart rate changes. Changes in the maximum positive rate of change in pressure (dP/dT) and maximum negative dP/dT were determined. Responses to varying doses of T3, T4, and isoproterenol were assessed in the presence and absence of beta-adrenergic receptor blockade with propranolol. cAMP production, measured by radioimmunoassay, was determined in myocardial cell suspensions after incubation with T3 or isoproterenol. Results T3 0.74 nmol rapidly and significantly increased maximum dP/dT by 335 +/- 38 mmHg/s within 30 s after bolus injection; however, contractility was unchanged after as much as 12.9 nmol T4. The maximal increase in dP/dT after 0.8 nmol isoproterenol was comparable to that produced by T3. However, the cardiotonic actions of isoproterenol were significantly slower to develop (peaking at 60 vs. 15 s) and lasted longer than those of T3. Pretreatment with propranolol 1 mumol diminished the contractile effects of isoproterenol but had no effect on those of T3. Concentrations of isoproterenol that increase contractility also significantly increased cAMP production in isolated rat myocardial cells. However, T3 failed to increase cAMP production. Conclusions These results demonstrate that the acute inotropic effects of T3 are not shared by T4 and appear unrelated to beta-adrenergic receptor mechanisms or to generation of cAMP. Thus, T3 acutely stimulates cardiac contraction by mechanisms that differ from those of the more commonly used beta-adrenergic receptor agonists and phosphodiesterase inhibitors. Further studies are needed to identify the mechanisms underlying the acute contractile effects of T3 and to determine whether T3 will prove useful for increasing ventricular function in patients.

Regulatory effects of phospholamban on cardiac function in intact mice

1997 ◽  
Vol 273 (6) ◽  
pp. H2826-H2831 ◽  
Author(s):  
John N. Lorenz ◽  
Evangelia G. Kranias
Keyword(s):  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Physiological Role ◽  
Cardiovascular Effects ◽  
Left Ventricular ◽  
In Vivo Evaluation ◽  
Intact Mouse ◽  
Cardiac Sarcoplasmic Reticulum ◽  
Inotropic Effects

Phospholamban (PLB) regulates Ca2+- adenosinetriphosphatase activity in cardiac sarcoplasmic reticulum and participates in the regulation of myocardial performance. Animal models with altered levels of PLB permit in vivo evaluation of the physiological role of PLB. This study examined left ventricular (LV) performance in intact PLB heterozygous and homozygous mice under basal and stimulated conditions. A Millar Mikro-Tip transducer was inserted into the right carotid artery and advanced into the LV for direct measurement of ventricular pressure and the first derivative of intraventricular pressure (dP/d t). Baseline blood pressures were increased in PLB heterozygotes and even more so in PLB homozygotes compared with wild types (WT), and there were no differences in heart rate or LV end-diastolic pressure. The increase in pressure was primarily caused by an increase in systolic pressure. Baseline values for positive and negative dP/d t were linearly correlated with PLB levels. In PLB heterozygotes, contractile response to isoproterenol (Iso) was blunted compared with WT, but maximum rates of contraction were similar between the two groups. Contractile performance in PLB homozygous mice, which under baseline conditions was similar to maximum levels seen in WT, showed a blunted response to Iso, and maximum rates of contraction were significantly greater than in either of the other groups, indicating an essential but perhaps not exclusive role for PLB in mediating the inotropic effects of β-adrenergic agonists. The effects of Iso on negative dP/d t were also blunted in both PLB heterozygous and PLB homozygous animals. Our results demonstrate that myocardial function is highly dependent on PLB level and suggest that the cardiovascular effects of PLB perturbations are largely uncompensated for in the intact mouse.

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