Role of EDRF in the cardiopulmonary dysfunction produced by massive sympathetic activation

1995 ◽  
Vol 78 (5) ◽  
pp. 1642-1650 ◽  
Author(s):  
C. F. Pilati ◽  
M. B. Maron ◽  
F. J. Bosso
Keyword(s):  
Pulmonary Edema ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Edema Formation ◽  
Systemic Hemodynamic ◽  
Lv Dysfunction ◽  
The Right

This study was undertaken to determine whether endothelium-derived relaxing factor (EDRF) modulates the pulmonary and systemic hemodynamic responses to massive sympathetic nervous system (SNS) activation and, in so doing, also modulates the degree of SNS-induced left ventricular (LV) dysfunction and the likelihood for pulmonary edema formation. The SNS of 13 anesthetized untreated rabbits and 14 anesthetized rabbits pretreated with the EDRF inhibitor, N omega-nitro-L-arginine (L-NNA, 20 mg/kg), was massively activated with an intracisternal injection of veratrine. Pulmonary and systemic arterial pressures increased to the same extent in both groups, but LV end-diastolic pressure was significantly lower in untreated rabbits. During this time, cardiac output decreased by 37% in L-NNA pretreated rabbits compared with 8% in untreated animals. Peak systemic and pulmonary vascular resistances increased significantly in L-NNA rabbits, whereas only systemic vascular resistance increased significantly in untreated rabbits. However, this increase in systemic vascular resistance was threefold less than that observed for L-NNA-treated animals. Although the degree of LV dysfunction was greater in the L-NNA rabbits, pulmonary edema developed less frequently in this group. We suggest that when EDRF release is inhibited during massive SNS activity, pulmonary vascular resistance increases markedly, which causes the right ventricle to fail. We further suggest that the reduced right ventricular output maintains pulmonary microvascular pressure below levels required for edema development.

Progressive myocardial dysfunction associated with increased vascular resistance

1980 ◽  
Vol 239 (4) ◽  
pp. H477-H477 ◽  
Author(s):  
Joseph A. Franciosa ◽  
Richard Heckel ◽  
Catherine Limas ◽  
Jay N. Cohn
Keyword(s):  
Heart Failure ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Diastolic Pressure ◽  
Myocardial Dysfunction ◽  
Peripheral Circulation ◽  
Left Ventricular ◽  
Stroke Work ◽  
Low Cardiac Output

To study heart failure from a myocardial lesion, we injected glass beads into the circumflex coronary artery of 11 conscious dogs and followed hemodynamics for 10 mo. Heart rate remained unchanged. Control mean arterial pressure of 112.3 ± 3.0 (SE) mmHg was unchanged at 1 and 3 mo, but rose to 127.2 ± 8.5 to 84.0 ± 7.6 ml . kg-1 . min-1 at 10 mo (P < 0.02), but was unchanged at 1 and 3 mo. Left ventricular end-diastolic pressure (LVEDP) averaged 4.6 ± 0.8 mmHg at control and rose to 11.8 ± 1.4 mmHg at 1 mo and 14.9 ± 2.5 mmHg at 10 mo (both P < 0.01). Systemic vascular resistance rose significantly by 10 mo. The ratio of stroke work to LVEDP fell from 13.1 ± 0.1 at control to 3.8 ± 0.5 by 10 mo (P < 0.01). In this dog model, left ventricular dysfunction is manifest early by increased LVEDP and later by high systemic vascular resistance with low cardiac output, thus suggesting a role of the peripheral circulation in the progression of heart failure.

The role of hypoxemia, vasoactive compounds, and acidemia in the pathogenesis of pulmonary edema in the dog with experimental left ventricular overload

1980 ◽  
Vol 58 (7) ◽  
pp. 849-855
Author(s):  
John S. Baumber
Keyword(s):  
Pulmonary Edema ◽  
Diastolic Pressure ◽  
Systolic Pressure ◽  
Plasma Renin ◽  
Left Ventricular ◽  
Left Heart Failure ◽  
Ventricular Systolic Pressure ◽  
Vasoactive Substances ◽  
Arterial Ph

The pathogenesis of pulmonary edema (PE) in left heart failure involves a consideration of the hydrostatic, osmotic, and permeability changes in the pulmonary circulation. In 14 dogs with isolated left ventricular overload induced by suturing a Teflon graft between the aorta and left atrium, left ventricular end-diastolic pressure (LVEDP) was 36 mmHg (1 mmHg = 133.322 Pa) 3 weeks following surgery. There was no clinical evidence of PE. Seven of these animals developed PE when allowed to breathe 10% O2 in N2 for 15 min. There was no further increase in LVEDP or right ventricular systolic pressure (RVSP). It was postulated that a change in permeability superimposed on increased capillary hydrostatic pressure could result in the overwhelming accumulation of fluid in the alveoli. The release of vasoactive substances from pulmonary mast cells or from the adrenal medulla might alter capillary permeability. However, the infusion of histamine or epinephrine in seven dogs with elevated LVEDP and RVSP failed to precipitate fulminating PE. We have previously observed an increase in plasma renin activity in dogs associated with PE. Nonpressor infusions of angiotensin failed to produce PE. The infusion of lactic acid to decrease the arterial pH to 7.00 (the level observed as a result of hypoxia-induced PE) resulted in fulminating PE. It is concluded that acidemia can be an important factor in the development of severe intra-alveolar pulmonary edema.

Hemodynamic effects of periodic obstructive apneas in sedated pigs with congestive heart failure

2000 ◽  
Vol 88 (3) ◽  
pp. 1051-1060 ◽  
Author(s):  
Ling Chen ◽  
Quihu Shi ◽  
Steven M. Scharf
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Mean Arterial Pressure ◽  
Arterial Pressure ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Air Breathing ◽  
Obstructive Sleep

Because of similar physiological changes such as increased left ventricular (LV) afterload and sympathetic tone, an exaggerated depression in cardiac output (CO) could be expected in patients with coexisting obstructive sleep apnea and congestive heart failure (CHF). To determine cardiovascular effects and mechanisms of periodic obstructive apnea in the presence of CHF, 11 sedated and chronically instrumented pigs with CHF (rapid pacing) were tested with upper airway occlusion under room air breathing (RA), O2 breathing (O2), and room air breathing after hexamethonium (Hex). All conditions led to large negative swings in intrathoracic pressure (−30 to −39 Torr) and hypercapnia ([Formula: see text] ∼60 Torr), and RA and Hex also caused hypoxia (to ∼42 Torr). Relative to baseline, RA increased mean arterial pressure (from 97.5 ± 5.0 to 107.3 ± 5.7 Torr, P < 0.01), systemic vascular resistance, LV end-diastolic pressure, and LV end-systolic length while it decreased CO (from 2.17 ± 0.27 to 1.52 ± 0.31 l/min, P < 0.01), stroke volume (SV; from 23.5 ± 2.4 to 16.0 ± 4.0 ml, P < 0.01), and LV end-diastolic length (LVEDL). O2 and Hex decreased mean arterial pressure [from 102.3 ± 4.1 to 16.0 ± 4.0 Torr ( P < 0.01) with O2 and from 86.0 ± 8.5 to 78.1 ± 8.7 Torr ( P < 0.05) with Hex] and blunted the reduction in CO [from 2.09 ± 0.15 to 1.78 ± 0.18 l/ml for O2 and from 2.91 ± 0.43 to 2.50 ± 0.35 l/ml for Hex (both P< 0.05)] and SV. However, the reduction in LVEDL and LV end-diastolic pressure was the same as with RA. There was no change in systemic vascular resistance and LVEDL during O2 and Hex relative to baseline. In the CHF pigs during apnea, there was an exaggerated reduction in CO and SV relative to our previously published data from normal sedated pigs under similar conditions. The primary difference between CHF (present study) and the normal animals is that, in addition to increased LV afterload, there was a decrease in LV preload in CHF contributing to SV depression not seen in normal animals. The decrease in LV preload during apneas in CHF may be related to effects of ventricular interdependence.

scholarly journals Empagliflozin does not change cardiac index nor systemic vascular resistance but rapidly improves left ventricular filling pressure in patients with type 2 diabetes: a randomized controlled study

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Matthias Rau ◽  
Kirsten Thiele ◽  
Niels-Ulrik Korbinian Hartmann ◽  
Alexander Schuh ◽  
Ertunc Altiok ◽  
...  
Keyword(s):  
Cardiac Index ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Resistance Index ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Volume Index ◽  
Hemodynamic Parameters ◽  
Mitral Inflow ◽  
Ventricular Filling Pressure

Abstract Background In the EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial) treatment with the sodium-glucose cotransporter-2 (SGLT2) inhibitor empagliflozin significantly reduced heart failure hospitalization (HHF) in patients with type 2 diabetes mellitus (T2D) and established cardiovascular disease. The early separation of the HHF event curves within the first 3 months of the trial suggest that immediate hemodynamic effects may play a role. However, hitherto no data exist on early effects of SGLT2 inhibitors on hemodynamic parameters and cardiac function. Thus, this study examined early and delayed effects of empagliflozin treatment on hemodynamic parameters including systemic vascular resistance index, cardiac index, and stroke volume index, as well as echocardiographic measures of cardiac function. Methods In this placebo-controlled, randomized, double blind, exploratory study patients with T2D were randomized to empagliflozin 10 mg or placebo for a period of 3 months. Hemodynamic and echocardiographic parameters were assessed after 1 day, 3 days and 3 months of treatment. Results Baseline characteristics were not different in the empagliflozin (n = 22) and placebo (n = 20) group. Empagliflozin led to a significant increase in urinary glucose excretion (baseline: 7.3 ± 22.7 g/24 h; day 1: 48.4 ± 34.7 g/24 h; p < 0.001) as well as urinary volume (1740 ± 601 mL/24 h to 2112 ± 837 mL/24 h; p = 0.011) already after one day compared to placebo. Treatment with empagliflozin had no effect on the primary endpoint of systemic vascular resistance index, nor on cardiac index, stroke volume index or pulse rate at any time point. In addition, echocardiography showed no difference in left ventricular systolic function as assessed by left ventricular ejections fraction and strain analysis. However, empagliflozin significantly improved left ventricular filling pressure as assessed by a reduction of early mitral inflow velocity relative to early diastolic left ventricular relaxation (E/eʹ) which became significant at day 1 of treatment (baseline: 9.2 ± 2.6; day 1: 8.5 ± 2.2; p = 0.005) and remained apparent throughout the study. This was primarily attributable to reduced early mitral inflow velocity E (baseline: 0.8 ± 0.2 m/s; day 1: 0.73 ± 0.2 m/sec; p = 0.003). Conclusions Empagliflozin treatment of patients with T2D has no significant effect on hemodynamic parameters after 1 or 3 days, nor after 3 months, but leads to rapid and sustained significant improvement of diastolic function. Trial registration EudraCT Number: 2016-000172-19; date of registration: 2017-02-20 (clinicaltrialregister.eu)

scholarly journals Empagliflozin does not change cardiac index nor systemic vascular resistance but rapidly improves left ventricular filling pressure in patients with type 2 diabetes: a randomized controlled study 

2020 ◽  
Author(s):  
Matthias Rau ◽  
Kirsten Thiele ◽  
Niels-Ulrik Korbinian Hartmann ◽  
Alexander Schuh ◽  
Ertunc Altiok ◽  
...  
Keyword(s):  
Cardiac Index ◽  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Resistance Index ◽  
Stroke Volume Index ◽  
Left Ventricular ◽  
Volume Index ◽  
Hemodynamic Parameters ◽  
Mitral Inflow ◽  
Ventricular Filling Pressure

Abstract Background: In the EMPA-REG OUTCOME trial (Empagliflozin Cardiovascular Outcome Event Trial) treatment with the sodium-glucose cotransporter-2 (SGLT2) inhibitor empagliflozin significantly reduced heart failure hospitalization (HHF) in patients with type 2 diabetes mellitus (T2D) and established cardiovascular disease. The early separation of the HHF event curves within the first 3 months of the trial suggest that immediate hemodynamic effects may play a role. However, hitherto no data exist on early effects of SGLT2 inhibitors on hemodynamic parameters and cardiac function. Thus, this study examined early and delayed effects of empagliflozin treatment on hemodynamic parameters including systemic vascular resistance index, cardiac index, and stroke volume index, as well as echocardiographic measures of cardiac function.Methods: In this placebo-controlled, randomized, double blind, exploratory study patients with T2D were randomized to empagliflozin 10 mg or placebo for a period of 3 months. Hemodynamic and echocardiographic parameters were assessed after 1 day, 3 days and 3 months of treatment. Results: Baseline characteristics were not different in the empagliflozin (n=22) and placebo (n=20) group. Empagliflozin led to a significant increase in urinary glucose excretion (baseline: 7.3 ± 22.7 g/24 hrs; day 1: 48.4 ± 34.7 g/24 hrs; p<0.001) as well as urinary volume (1740 ± 601 mL/24 hrs to 2112 ± 837 mL/24 hrs; p=0.011) already after one day compared to placebo. Treatment with empagliflozin had no effect on the primary endpoint of systemic vascular resistance index, nor on cardiac index, stroke volume index or pulse rate at any time point. In addition, echocardiography showed no difference in left ventricular systolic function as assessed by left ventricular ejections fraction and strain analysis. However, empagliflozin significantly improved left ventricular filling pressure as assessed by a reduction of early mitral inflow velocity relative to early diastolic left ventricular relaxation (E/e’) which became significant at day 1 of treatment (baseline: 9.2 ± 2.6; day 1: 8.5 ± 2.2; p=0.005) and remained apparent throughout the study. This was primarily attributable to reduced early mitral inflow velocity E (baseline: 0.8 ± 0.2 m/sec; day 1: 0.73 ± 0.2 m/sec; p=0.003). Conclusions: Empagliflozin treatment of patients with T2D has no significant effect on hemodynamic parameters after 1 or 3 days, nor after 3 months, but leads to rapid and sustained significant improvement of diastolic function.

scholarly journals Relaxin Modifies Systemic Arterial Resistance and Compliance in Conscious, Nonpregnant Rats

Endocrinology ◽  
2004 ◽  
Vol 145 (7) ◽  
pp. 3289-3296 ◽  
Author(s):  
Kirk P. Conrad ◽  
Dan O. Debrah ◽  
Jackie Novak ◽  
Lee A. Danielson ◽  
Sanjeev G. Shroff
Keyword(s):  
Systemic Vascular Resistance ◽  
Vascular Resistance ◽  
Therapeutic Potential ◽  
Muscle Tone ◽  
Arterial Compliance ◽  
Renal Arteries ◽  
Conscious Rat ◽  
Systemic Hemodynamic ◽  
Arterial Load ◽  
Passive Mechanics

Abstract Relaxin emanates from the corpus luteum of the ovary and circulates during pregnancy. Because the hormone is a potent renal vasodilator and mediates the renal vasodilation and hyperfiltration of pregnancy in conscious rats, we reasoned that it might also contribute to the broader cardiovascular changes of pregnancy. We began investigating this concept by testing whether relaxin can modify systemic arterial hemodynamics and load when chronically administered to nonpregnant rats. The major objectives of the present work were to determine whether relaxin administration to nonpregnant rats 1) modifies cardiac output (CO), systemic vascular resistance, and global arterial compliance (AC), and 2) regulates the passive mechanics of isolated arteries. To accomplish the first objective, we developed a conscious rat model for assessment of global AC. Passive mechanics of small renal arteries were assessed using a pressure arteriograph. Chronic administration of recombinant human relaxin by sc osmotic minipump to conscious, female, nonpregnant rats reduced the steady arterial load by decreasing systemic vascular resistance, increased CO, and reduced the pulsatile arterial load by increasing global AC as quantified by two indices—AC estimated from the diastolic decay of aortic pressure and CO and AC estimated by the ratio of stroke volume-to-pulse pressure. In another group of rats, relaxin administration also regulated the passive mechanics of small renal arteries, indicating that, in addition to reduction in vascular smooth muscle tone, modification of the vascular structure (e.g. extracellular matrix) contributes to the increase in global AC. These findings suggest a role for relaxin in the systemic hemodynamic changes of pregnancy, as well as novel therapeutic potential for relaxin in modifying arterial stiffness and cardiac afterload.

Abstract P050: Novel Mechanism of Ser-496 ERK5 Phosphorylation and Association with p90RSK Is Critical for Regulating C Terminus of Hsc70-Interacting Protein (CHIP) Ubiquitin E3 Ligase Activity in Diabetes-Mediated Exacerbation of Cardiomyocyte Apoptosis and Left Ventricular Dysfunction After Myocardial Infarction

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Nhat-Tu Le ◽  
Yuichiro Takei ◽  
Chang-Hoon Woo ◽  
Tetsuro Shishido ◽  
Yan Lu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Cardiac Dysfunction ◽  
Critical Role ◽  
Active Form ◽  
E3 Ligase ◽  
Left Ventricular ◽  
Ang Ii ◽  
Lv Dysfunction ◽  
On Chip

Rationale: Cardiac dysfunction is accelerated in DM patients after MI. Previously, we reported the critical role of ERK5 and CHIP association on CHIP Ub E3 ligase activity, which inhibits inducible cAMP early repressor (ICER)-mediated apoptosis and left ventricle (LV) dysfunction after MI in DM (DM + MI). Yet the regulatory mechanism of ERK5-CHIP has not been established. Objective: Since we found that p90RSK activation was increased in DM heart, we investigated whether p90RSK activation may inhibit ERK5-mediated CHIP activation, and subsequent ICER induction and apoptosis. Methods and Results: The inhibition of p90RSK activation prevented the reduction of ERK5-CHIP binding, CHIP activity, as well as ICER induction and cardiac apoptosis both in vitro after angiotensin II (ang II) stimulation and in vivo after DM + MI. p90RSK and CHIP share a same binding site with ERK5 C-terminal domain (aa571–807), and overexpression of both p90RSK and ERK5 (aa571–807) fragment, but not kinase dead mutant of p90RSK, inhibited ERK5-CHIP association, suggesting the critical role of p90RSK activation on ERK5-CHIP interaction, and competitive nature of p90RSK and CHIP against ERK5 association. Furthermore. LC-MS/MS analysis identified ERK5-S496 as being directly phosphorylated by p90RSK, and ERK5 S496A mutant significantly impaired ang II-mediated inhibition of CHIP Ub ligase activity, suggesting the critical role of Ser-496 phoaphorylation of ERK5 on CHIP activity. Therefore, p90RSK activation is critical for both p90RSK-ERK5 association as well as ERK5-Ser496 phosphorylation, and following disruption of ERK5-CHIP interaction and subsequent inhibition of CHIP Ub ligase activity. The reduction of CHIP Ub ligase activity and LV dysfunction were accelerated both in cardio-specific ERK5 knock out and wild type p90RSK transgenic mice (WT-p90RSK-Tg). Furthermore, double transgenic mice of WT-p90RSK and constitutively active form of MEK5α (specific ERK5 activator) inhibited single WT-p90RSK-Tg-medaited reduction of CHIP Ub ligase activity, LV dysfunction, and improved mortality after MI. Conclusions: These data strongly suggested that p90RSK activation accelerated cardiac dysfunction and apoptosis after DM + MI via inhibiting ERK5-CHIP module.

Abstract 3474: Cardiac -Specific SOCS3 Dificient Mice Shows Resistance to Lipopolysaccharide-Induced Cardiac Dysfunction

Circulation ◽  
2008 ◽  
Vol 118 (suppl_18) ◽  
Author(s):  
Futamata Nobuyoshi ◽  
Hldeo Yasukawa ◽  
Toyoharu Ohba ◽  
Kazutoshi Mawatari ◽  
Daisuke Fukui ◽  
...  
Keyword(s):  
Western Blot ◽  
Left Ventricular ◽  
Negative Regulator ◽  
Left Ventricular Ejection ◽  
Cytokine Signaling ◽  
Rt Pcr ◽  
Lv Dysfunction ◽  
Stat3 Signaling ◽  
Cardiomyocyte Survival

Background : Lypopolysaccharide (LPS)-induced left ventricular (LV) dysfunction is a well-established model for sepsis-induced acute heart failure. STAT3 signaling in the heart has been shown to promote cardiomyocyte survival during LPS-induced LV dysfunction. Little is known, however, about the role of negative regulation of STAT3 signaling during LPS-induced LV dysfunction. Suppressor of cytokine signaling 3 (SOCS3) is an intrinsic negative regulator of gp130 cytokine-induced STAT3 signaling that plays an important role in cardiomyocyte survival. In this study, we determined whether STAT3 signaling and its negative regulator SOCS3 would play a role in LPS-induced LV dysfunction. Methods and Results : We examined the activation of STAT3 and inductions of gp130 cytokines and SOCS3 in the wild-type (WT) mice hearts after LPS injection by western blot and real-time PCR (RT-PCR). RT-PCR revealed that gp130 cytokines were markedly increased after AMI. Western blot revealed that STAT3 was markedly phosphorylated and SOCS3 was induced in WT mice hearts after LPS injection. To investigate the role of STAT3 signaling and SOCS3 in LPS-induced LV dysfunction, we generated cardiac-specific SOCS3 knockout mice (SOCS3-CKO). Left ventricular ejection fraction (LVEF) of SOCS3-CKO mice was similar to that of WT mice at baseline (64.2 ± 6.1 vs. 62.4 ± 4.4%). LPS (30mg/kg) elicited a significant and robust reduction of LVEF in both SOCS3-CKO mice and WT mice 3 hr after LPS injection (18 ± 4.5 vs. 16 ± 5.2%, p <0.01). LVEF in WT mice was further reduced 6 hr after LPS injection. On the other hand, interestingly, LVEF was restored to the baseline in SOCS3-CKO mice 6 hr after LPS injection (10.4 ± 3.9 vs. 62.2 ± 8.1%, p <0.01). Also the duration and intensity of STAT3 phosphorylation after LPS injection was greater in SOCS3-CKO mice than WT mice. Furthermore, SOCS3-CKO mice showed greater survival rate than WT mice after LPS injection ( p <0.01). Conclusion : Our data show that the deletion of SOCS3 in cardiomyocytes prevents the LPS-induced LV dysfunction in mice, possibly by augmenting the STAT3-mediated gp130 cytokine signaling.

Renal sympathetic nerve regulation to heating is altered in rats with heart failure

2001 ◽  
Vol 280 (6) ◽  
pp. H2868-H2875 ◽  
Author(s):  
Michael J. Kenney ◽  
Timothy I. Musch ◽  
Mark L. Weiss
Keyword(s):  
Heart Failure ◽  
Sympathetic Nerve ◽  
Acute Stress ◽  
Diastolic Pressure ◽  
Left Ventricular ◽  
Whole Body ◽  
Neural Pathways ◽  
The Right ◽  
Colonic Temperature ◽  
Bilateral Lesions

Heart failure (HF) alters the regulation of basal sympathetic nerve discharge (SND); however, the effect of HF on SND responses to acute stress is not well established. In the present study, renal SND responses to hyperthermia were determined in chloralose-anesthetized HF rats and in sham controls. Whole body heating (colonic temperature increased from 38 to 41°C) was used as an acute stressor because increased internal body temperature provides a potent stimulus to the sympathetic nervous system. Left ventricular end-diastolic pressure and the right ventricular wt-to-body wt ratio were increased ( P < 0.05) in HF compared with sham rats. The following observations were made: 1) renal sympathoexcitatory responses to heating were significantly reduced in HF compared with sham rats, 2) renal blood flow remained unchanged from control levels during heating in HF rats but was significantly reduced in sham rats, and 3) renal SND responses to heating were significantly higher in HF rats with bilateral lesions of the hypothalamic paraventricular nucleus (PVN) compared with sham PVN-lesioned HF rats. These results demonstrate a marked attenuation in the responsiveness of renal SND to heating in HF rats and suggest that HF alters the organization of neural pathways mediating SND responses to heating.

Nitric oxide modulates epicardial coronary basal vasomotor tone in awake dogs

1990 ◽  
Vol 258 (4) ◽  
pp. H1250-H1254 ◽  
Author(s):  
A. Chu ◽  
D. E. Chambers ◽  
C. C. Lin ◽  
W. D. Kuehl ◽  
F. R. Cobb
Keyword(s):  
Nitric Oxide ◽  
Coronary Flow ◽  
Diastolic Pressure ◽  
Coronary Vessels ◽  
Aortic Pressure ◽  
Left Ventricular ◽  
Vasomotor Tone ◽  
Coronary Vasomotor Tone ◽  
Endogenous Nitric Oxide

This study evaluates the role of endogenous nitric oxide in the modulation of basal coronary vasomotor tone by studying the effects of NG-monomethyl-L-arginine (L-NMMA), an inhibitor of nitric oxide formation from L-arginine, on resting epicardial coronary diameter and coronary flow. L-NMMA (5 mg/kg) was infused in seven awake dogs chronically instrumented with coronary dimension crystals for measurement of epicardial coronary diameter, and Doppler flow probes for quantitation of phasic coronary flow (vasomotion of distal regulatory resistance coronary vessels). Epicardial coronary diameter decreased 5.5% from 3.47 +/- 0.17 to 3.28 +/- 0.15 mm (mean +/- SE). The diameter change was gradual, reaching a maximum at 13 +/- 2 min after infusion, and persistent, lasting greater than 90 min. Phasic coronary flow did not change. Mean aortic pressure significantly increased from 99 +/- 3 to 111 +/- 3 mmHg and heart rate decreased from 56 +/- 4 to 46 +/- 3 beats/min. Left ventricular end-diastolic pressure and contractility were not significantly altered. L-Arginine (66 mg/kg) but not D-arginine reversed all hemodynamic parameters. These data support an important role of nitric oxide in modulating basal epicardial coronary vasomotor tone and systemic vascular resistance.

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