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Intrinsic cardiac neurons of the adult pigs: chemical types, abundance, parameters and distribution within ganglionated plexus. Ann Anat 2022; 243:151935. [DOI: 10.1016/j.aanat.2022.151935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Revised: 03/04/2022] [Accepted: 03/09/2022] [Indexed: 11/18/2022]
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Hu W, Zhang D, Tu H, Li YL. Reduced Cell Excitability of Cardiac Postganglionic Parasympathetic Neurons Correlates With Myocardial Infarction-Induced Fatal Ventricular Arrhythmias in Type 2 Diabetes Mellitus. Front Neurosci 2021; 15:721364. [PMID: 34483832 PMCID: PMC8416412 DOI: 10.3389/fnins.2021.721364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/30/2021] [Indexed: 01/09/2023] Open
Abstract
Objective Withdrawal of cardiac vagal activity is considered as one of the important triggers for acute myocardial infarction (MI)-induced ventricular arrhythmias in type 2 diabetes mellitus (T2DM). Our previous study demonstrated that cell excitability of cardiac parasympathetic postganglionic (CPP) neurons was reduced in T2DM rats. This study investigated whether cell excitability of CPP neurons is associated with cardiac vagal activity and MI-induced ventricular arrhythmias in T2DM rats. Methods Rat T2DM was induced by a high-fat diet plus streptozotocin injection. MI-evoked ventricular arrhythmia was achieved by surgical ligation of the left anterior descending coronary artery. Twenty-four-hour, continuous ECG recording was used to quantify ventricular arrhythmic events and heart rate variability (HRV) in conscious rats. The power spectral analysis of HRV was used to evaluate autonomic function. Cell excitability of CPP neurons was measured by the whole-cell patch-clamp technique. Results Twenty-four-hour ECG data demonstrated that MI-evoked fatal ventricular arrhythmias are more severe in T2DM rats than that in sham rats. In addition, the Kaplan-Meier analysis demonstrated that the survival rate over 2 weeks after MI is significantly lower in T2DM rats (15% in T2DM+MI) compared to sham rats (75% in sham+MI). The susceptibility to ventricular tachyarrhythmia elicited by programmed electrical stimulation was higher in anesthetized T2DM+MI rats than that in rats with MI or T2DM alone (7.0 ± 0.58 in T2DM+MI group vs. 3.5 ± 0.76 in sham+MI). Moreover, as an index for vagal control of ventricular function, changes of left ventricular systolic pressure (LVSP) and the maximum rate of increase of left ventricular pressure (LV dP/dtmax) in response to vagal efferent nerve stimulation were blunted in T2DM rats. Furthermore, T2DM increased heterogeneity of ventricular electrical activities and reduced cardiac parasympathetic activity and cell excitability of CPP neurons (current threshold-inducing action potentials being 62 ± 3.3 pA in T2DM rats without MI vs. 27 ± 1.9 pA in sham rats without MI). However, MI did not alter vagal control of the ventricular function and CPP neuronal excitability, although it also induced cardiac autonomic dysfunction and enhanced heterogeneity of ventricular electrical activities. Conclusion The reduction of CPP neuron excitability is involved in decreased cardiac vagal function, including cardiac parasympathetic activity and vagal control of ventricular function, which is associated with MI-induced high mortality and malignant ventricular arrhythmias in T2DM.
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Affiliation(s)
- Wenfeng Hu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Cellular & Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
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Heart rate variability (HRV): From brain death to resonance breathing at 6 breaths per minute. Clin Neurophysiol 2020; 131:676-693. [DOI: 10.1016/j.clinph.2019.11.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2019] [Revised: 10/14/2019] [Accepted: 11/06/2019] [Indexed: 12/13/2022]
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Soucy JR, Askaryan J, Diaz D, Koppes AN, Annabi N, Koppes RA. Glial cells influence cardiac permittivity as evidenced through in vitro and in silico models. Biofabrication 2019; 12:015014. [PMID: 31593932 PMCID: PMC11062241 DOI: 10.1088/1758-5090/ab4c0a] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Excitation-contraction (EC) coupling in the heart has, until recently, been solely accredited to cardiomyocytes. The inherent complexities of the heart make it difficult to examine non-muscle contributions to contraction in vivo, and conventional in vitro models fail to capture multiple features and cellular heterogeneity of the myocardium. Here, we report on the development of a 3D cardiac μTissue to investigate changes in the cellular composition of native myocardium in vitro. Cells are encapsulated within micropatterned gelatin-based hydrogels formed via visible light photocrosslinking. This system enables spatial control of the microarchitecture, perturbation of the cellular composition, and functional measures of EC coupling via video microscopy and a custom algorithm to quantify beat frequency and degree of coordination. To demonstrate the robustness of these tools and evaluate the impact of altered cell population densities on cardiac μTissues, contractility and cell morphology were assessed with the inclusion of exogenous non-myelinating Schwann cells (SCs). Results demonstrate that the addition of exogenous SCs alter cardiomyocyte EC, profoundly inhibiting the response to electrical pacing. Computational modeling of connexin-mediated coupling suggests that SCs impact cardiomyocyte resting potential and rectification following depolarization. Cardiac μTissues hold potential for examining the role of cellular heterogeneity in heart health, pathologies, and cellular therapies.
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Affiliation(s)
- Jonathan R Soucy
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, United States of America
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Pickard JMJ, Davidson SM, Hausenloy DJ, Yellon DM. Co-dependence of the neural and humoral pathways in the mechanism of remote ischemic conditioning. Basic Res Cardiol 2016; 111:50. [PMID: 27338249 PMCID: PMC4919370 DOI: 10.1007/s00395-016-0568-z] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 06/16/2016] [Indexed: 12/16/2022]
Abstract
The cardioprotection afforded by remote ischaemic conditioning (RIC) is mediated via a complex mechanism involving sensory afferent nerves, the vagus nerve, and release of a humoral blood-borne factor. However, it is unknown whether release of the protective factor depends on vagal activation or occurs independently. This study aimed to evaluate the co-dependence of the neural and humoral pathways of RIC, focussing on the vagus nerve and intrinsic cardiac ganglia. In the first study, anesthetised rats received bilateral cervical vagotomy or sham-surgery immediately prior to RIC (4 × 5 min limb ischemia–reperfusion) or sham-RIC. Venous blood plasma was dialysed across a 12–14 kDa membrane and dialysate perfused through a naïve-isolated rat heart prior to 35-min left anterior descending ischemia and 60-min reperfusion. In the second study, anesthetised rats received RIC (4 × 5-min limb ischemia–reperfusion) or control (sham-RIC). Dialysate was prepared and perfused through a naïve-isolated rat heart in the presence of the ganglionic blocker hexamethonium or muscarinic antagonist atropine, prior to ischemia–reperfusion as above. Dialysate collected from RIC-treated rats reduced infarct size in naïve rat hearts from 40.7 ± 6.3 to 23.7 ± 3.1 %, p < 0.05. Following bilateral cervical vagotomy, the protection of RIC dialysate was abrogated (42.2 ± 3.2 %, p < 0.05 vs RIC dialysate). In the second study, the administration of 50-μM hexamethonium (45.8 ± 2.5 %) or 100-nM atropine (36.5 ± 3.4 %) abrogated the dialysate-mediated protection. Release of a protective factor following RIC is dependent on prior activation of the vagus nerve. In addition, this factor appears to induce cardioprotection via recruitment of intrinsic cardiac ganglia.
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Affiliation(s)
- Jack M J Pickard
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
| | - Sean M Davidson
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK
| | - Derek J Hausenloy
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK.,Cardiovascular and Metabolic Disorders Program, Duke-NUS Graduate Medical School, Singapore, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore
| | - Derek M Yellon
- The Hatter Cardiovascular Institute, University College London, 67 Chenies Mews, London, WC1E 6HX, UK.
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Nakamura K, Ajijola OA, Aliotta E, Armour JA, Ardell JL, Shivkumar K. Pathological effects of chronic myocardial infarction on peripheral neurons mediating cardiac neurotransmission. Auton Neurosci 2016; 197:34-40. [PMID: 27209472 DOI: 10.1016/j.autneu.2016.05.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To determine whether chronic myocardial infarction (MI) induces structural and neurochemical changes in neurons within afferent and efferent ganglia mediating cardiac neurotransmission. METHODS Neuronal somata in i) right atrial (RAGP) and ii) ventral interventricular ganglionated plexi (VIVGP), iii) stellate ganglia (SG) and iv) T1-2 dorsal root ganglia (DRG) bilaterally derived from normal (n=8) vs. chronic MI (n=8) porcine subjects were studied. We examined whether the morphology and neuronal nitric oxide synthase (nNOS) expression in soma of RAGP, VIVGP, DRG and SG neurons were altered as a consequence of chronic MI. In DRG, we also examined immunoreactivity of calcitonin gene related peptide (CGRP), a marker of afferent neurons. Chronic MI increased neuronal size and nNOS immunoreactivity in VIVGP (but not RAGP), as well as in the SG bilaterally. Across these ganglia, the increase in neuronal size was more pronounced in nNOS immunoreactive neurons. In the DRG, chronic MI also caused neuronal enlargement, and increased CGRP immunoreactivity. Further, DRG neurons expressing both nNOS and CGRP were increased in MI animals compared to controls, and represented a shift from double negative neurons. CONCLUSIONS Chronic MI impacts diverse elements within the peripheral cardiac neuraxis. That chronic MI imposes such widespread, diverse remodeling of the peripheral cardiac neuraxis must be taken into consideration when contemplating neuronal regulation of the ischemic heart.
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Affiliation(s)
- Keijiro Nakamura
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, University of California, Los Angeles, CA, USA; Department of Radiology, University of California, Los Angeles, CA, USA
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, University of California, Los Angeles, CA, USA; Department of Radiology, University of California, Los Angeles, CA, USA.
| | - Eric Aliotta
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, University of California, Los Angeles, CA, USA; Department of Radiology, University of California, Los Angeles, CA, USA
| | - J Andrew Armour
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, University of California, Los Angeles, CA, USA; Department of Radiology, University of California, Los Angeles, CA, USA
| | - Jeffrey L Ardell
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, University of California, Los Angeles, CA, USA; Department of Radiology, University of California, Los Angeles, CA, USA
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Center of Excellence, University of California, Los Angeles, CA, USA; Department of Radiology, University of California, Los Angeles, CA, USA
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Kapa S, DeSimone CV, Asirvatham SJ. Innervation of the heart: An invisible grid within a black box. Trends Cardiovasc Med 2016; 26:245-57. [PMID: 26254961 PMCID: PMC4706824 DOI: 10.1016/j.tcm.2015.07.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 06/30/2015] [Accepted: 07/02/2015] [Indexed: 02/07/2023]
Abstract
Autonomic control of cardiovascular function is mediated by a complex interplay between central, peripheral, and innate cardiac components. This interplay is what mediates the normal cardiovascular response to physiologic and pathologic stressors, including blood pressure, cardiac contractile function, and arrhythmias. However, in order to understand how modern therapies directly affecting autonomic function may be harnessed to treat various cardiovascular disease states requires an intimate understanding of anatomic and physiologic features of the innervation of the heart. Thus, in this review, we focus on defining features of the central, peripheral, and cardiac components of cardiac innervation, how each component may contribute to dysregulation of normal cardiac function in various disease states, and how modulation of these components may offer therapeutic options for these diseases.
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Affiliation(s)
- Suraj Kapa
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Christopher V DeSimone
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN
| | - Samuel J Asirvatham
- Division of Cardiovascular Diseases, Department of Medicine, Mayo Clinic College of Medicine, Rochester, MN; Division of Pediatric Cardiology, Department of Pediatrics and Adolescent Medicine, Mayo Clinic College of Medicine, Rochester, MN.
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Shaffer F, McCraty R, Zerr CL. A healthy heart is not a metronome: an integrative review of the heart's anatomy and heart rate variability. Front Psychol 2014; 5:1040. [PMID: 25324790 PMCID: PMC4179748 DOI: 10.3389/fpsyg.2014.01040] [Citation(s) in RCA: 831] [Impact Index Per Article: 83.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/31/2014] [Indexed: 12/13/2022] Open
Abstract
Heart rate variability (HRV), the change in the time intervals between adjacent heartbeats, is an emergent property of interdependent regulatory systems that operate on different time scales to adapt to challenges and achieve optimal performance. This article briefly reviews neural regulation of the heart, and its basic anatomy, the cardiac cycle, and the sinoatrial and atrioventricular pacemakers. The cardiovascular regulation center in the medulla integrates sensory information and input from higher brain centers, and afferent cardiovascular system inputs to adjust heart rate and blood pressure via sympathetic and parasympathetic efferent pathways. This article reviews sympathetic and parasympathetic influences on the heart, and examines the interpretation of HRV and the association between reduced HRV, risk of disease and mortality, and the loss of regulatory capacity. This article also discusses the intrinsic cardiac nervous system and the heart-brain connection, through which afferent information can influence activity in the subcortical and frontocortical areas, and motor cortex. It also considers new perspectives on the putative underlying physiological mechanisms and properties of the ultra-low-frequency (ULF), very-low-frequency (VLF), low-frequency (LF), and high-frequency (HF) bands. Additionally, it reviews the most common time and frequency domain measurements as well as standardized data collection protocols. In its final section, this article integrates Porges' polyvagal theory, Thayer and colleagues' neurovisceral integration model, Lehrer et al.'s resonance frequency model, and the Institute of HeartMath's coherence model. The authors conclude that a coherent heart is not a metronome because its rhythms are characterized by both complexity and stability over longer time scales. Future research should expand understanding of how the heart and its intrinsic nervous system influence the brain.
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Affiliation(s)
- Fred Shaffer
- Center for Applied Psychophysiology, Department of Psychology, Truman State University Kirksville, MO, USA
| | - Rollin McCraty
- HeartMath Research Center, Institute of HeartMath Boulder Creek, CA, USA
| | - Christopher L Zerr
- Center for Applied Psychophysiology, Department of Psychology, Truman State University Kirksville, MO, USA
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Revisiting heart activation-conduction physiology, part I: atria. J Interv Card Electrophysiol 2014; 40:9-15. [PMID: 24671296 DOI: 10.1007/s10840-014-9884-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2013] [Accepted: 02/04/2014] [Indexed: 10/25/2022]
Abstract
This discussion paper re-examines the conduction-activation of the atria, based on observations, with respect to the complexity of the heart as an organ with a brain, and its evolution from a peristaltic tube. The atria do not require a specialized conduction system because they use the subendocardial layer to produce centripetal transmural activation fronts, regardless of the anatomical and histological organization of the transmural atrial wall. This has been described as "two-layer" physiology which provides robust transmission of activation from the sinus to the AV node via a centripetal transmural activation front. New productive insights can come from re-examining the physiology, not only during sinus rhythm but also during atrial tachycardias, in particular atrial flutter and atrial fibrillation (AF). During common flutter, the areas of slow conduction, in the isthmus and following trabeculations, particularly the subendocardial layer confines conduction through the trabeculations which supports re-entry. During experimental or postoperative flutter, the circular 2D activation around the obstacle follows the physiological transmural activation. Understanding this physiology offers insights into AF. During acute or protracted AF, the presence of stationary or drifting rotors is characteristic and consistent with normal physiological 2D atrial activation, suggesting that suppressing physiological transmural activation of AF will permanently restore normal sinus node atrial activation. In contrast, during permanent AF, normal 2D activation is abolished; the presence of transmural, serpentine, and chaotic atrial activation suggests that the normal physiological activation pattern has been replaced by a new, irreversible variety of atrial conduction that is a new physiology, which is consistent with evolution of complex systems.
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Rajendran PS, Buch E, Shivkumar K. Marshaling the autonomic nervous system for treatment of atrial fibrillation. J Am Coll Cardiol 2014; 63:1902-3. [PMID: 24561143 DOI: 10.1016/j.jacc.2014.01.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Accepted: 01/20/2014] [Indexed: 01/20/2023]
Affiliation(s)
- Pradeep S Rajendran
- UCLA Cardiac Arrhythmia Center, UCLA, Los Angeles, California; David Geffen School of Medicine, UCLA, Los Angeles, California; Molecular, Cellular and Integrative Physiology Program, UCLA, Los Angeles, California; Neurocardiology Program, Center for Neurobiology of Stress, UCLA, Los Angeles, California
| | - Eric Buch
- UCLA Cardiac Arrhythmia Center, UCLA, Los Angeles, California; David Geffen School of Medicine, UCLA, Los Angeles, California
| | - Kalyanam Shivkumar
- UCLA Cardiac Arrhythmia Center, UCLA, Los Angeles, California; David Geffen School of Medicine, UCLA, Los Angeles, California; Molecular, Cellular and Integrative Physiology Program, UCLA, Los Angeles, California; Neurocardiology Program, Center for Neurobiology of Stress, UCLA, Los Angeles, California.
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Tu H, Liu J, Zhang D, Zheng H, Patel KP, Cornish KG, Wang WZ, Muelleman RL, Li YL. Heart failure-induced changes of voltage-gated Ca2+ channels and cell excitability in rat cardiac postganglionic neurons. Am J Physiol Cell Physiol 2013; 306:C132-42. [PMID: 24025863 DOI: 10.1152/ajpcell.00223.2013] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Chronic heart failure (CHF) is characterized by decreased cardiac parasympathetic and increased cardiac sympathetic nerve activity. This autonomic imbalance increases the risk of arrhythmias and sudden death in patients with CHF. We hypothesized that the molecular and cellular alterations of cardiac postganglionic parasympathetic (CPP) neurons located in the intracardiac ganglia and sympathetic (CPS) neurons located in the stellate ganglia (SG) possibly link to the cardiac autonomic imbalance in CHF. Rat CHF was induced by left coronary artery ligation. Single-cell real-time PCR and immunofluorescent data showed that L (Ca(v)1.2 and Ca(v)1.3), P/Q (Ca(v)2.1), N (Ca(v)2.2), and R (Ca(v)2.3) types of Ca2+ channels were expressed in CPP and CPS neurons, but CHF decreased the mRNA and protein expression of only the N-type Ca2+ channels in CPP neurons, and it did not affect mRNA and protein expression of all Ca2+ channel subtypes in the CPS neurons. Patch-clamp recording confirmed that CHF reduced N-type Ca2+ currents and cell excitability in the CPP neurons and enhanced N-type Ca2+ currents and cell excitability in the CPS neurons. N-type Ca2+ channel blocker (1 μM ω-conotoxin GVIA) lowered Ca2+ currents and cell excitability in the CPP and CPS neurons from sham-operated and CHF rats. These results suggest that CHF reduces the N-type Ca2+ channel currents and cell excitability in the CPP neurons and enhances the N-type Ca2+ currents and cell excitability in the CPS neurons, which may contribute to the cardiac autonomic imbalance in CHF.
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Affiliation(s)
- Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, Nebraska
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Liu J, Tu H, Zheng H, Zhang L, Tran TP, Muelleman RL, Li YL. Alterations of calcium channels and cell excitability in intracardiac ganglion neurons from type 2 diabetic rats. Am J Physiol Cell Physiol 2011; 302:C1119-27. [PMID: 22189553 DOI: 10.1152/ajpcell.00315.2011] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Clinical study has demonstrated that patients with type 2 diabetes with attenuated arterial baroreflex have higher mortality rate compared with those without arterial baroreflex dysfunction. As a final pathway for the neural control of the cardiac function, functional changes of intracardiac ganglion (ICG) neurons might be involved in the attenuated arterial baroreflex in the type 2 diabetes mellitus (T2DM). Therefore, we measured the ICG neuron excitability and Ca(2+) channels in the sham and T2DM rats. T2DM was induced by a combination of both high-fat diet and low-dose streptozotocin (STZ, 30 mg/kg ip) injection. After 12-14 wk of the above treatment, the T2DM rats presented hyperglycemia, hyperlipidemia, and insulin resistance but no hyperinsulinemia, which closely mimicked the clinical features of the patients with T2DM. Data from immunofluorescence staining showed that L, N, P/Q, and R types of Ca(2+) channels were expressed in the ICG neurons, but only protein expression of N-type Ca(2+) channels was decreased in the ICG neurons from T2DM rats. Using whole cell patch-clamp technique, we found that T2DM significantly reduced the Ca(2+) currents and cell excitability in the ICG neurons. ω-Conotoxin GVIA (a specific N-type Ca(2+) channel blocker, 1 μM) lowered the Ca(2+) currents and cell excitability toward the same level in sham and T2DM rats. These results indicate that the decreased N-type Ca(2+) channels contribute to the suppressed ICG neuron excitability in T2DM rats. From this study, we think high-fat diet/STZ injection-induced T2DM might be an appropriate animal model to test the cellular and molecular mechanisms of cardiovascular autonomic dysfunction.
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Affiliation(s)
- Jinxu Liu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, 68198-5850, USA
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Nair K, Waxman M, Farid T, Nanthakumar K. Intrinsic neural reflexes in the post-transplant human heart. Europace 2009; 12:292-3. [DOI: 10.1093/europace/eup359] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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15
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Almela P, Cerezo M, González-Cuello A, Milanés MV, Laorden ML. Differential involvement of 3′, 5′-cyclic adenosine monophosphate-dependent protein kinase in regulation of Fos and tyrosine hydroxylase expression in the heart after naloxone induced morphine withdrawal. Naunyn Schmiedebergs Arch Pharmacol 2006; 374:293-303. [PMID: 17216288 DOI: 10.1007/s00210-006-0120-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2006] [Accepted: 11/02/2006] [Indexed: 11/25/2022]
Abstract
We previously demonstrated that morphine withdrawal induced hyperactivity of the heart by the activation of noradrenergic pathways innervating the left and right ventricle, as evaluated by noradrenaline (NA) turnover and Fos expression. We investigated whether cAMP-dependent protein kinase (PKA) plays a role in this process by estimating changes in PKA immunoreactivity and the influence of inhibitor of PKA on Fos protein expression, tyrosine hydroxylase (TH) immunoreactivity levels and NA turnover in the left and right ventricle. Dependence on morphine was induced by a 7-day s.c. implantation of morphine pellets. Morphine withdrawal was precipitated on day 8 by an injection of naloxone (5 mg/kg). When opioid withdrawal was precipitated, an increase in PKA immunoreactivity and phospho-CREB (cyclic AMP response element protein) levels were observed in the heart. Moreover, morphine withdrawal induces Fos expression, an enhancement of NA turnover and an increase in the total TH levels. When the selective PKA inhibitor HA-1004 was infused, concomitantly with morphine pellets, it diminished the increase in NA turnover and the total TH levels observed in morphine-withdrawn rats. However, this inhibitor neither modifies the morphine withdrawal induced Fos expression nor the increase of nonphosphorylated TH levels. The present findings indicate that an up-regulated PKA-dependent transduction pathway might contribute to the activation of the cardiac catecholaminergic neurons in response to morphine withdrawal and suggest that Fos is not a target of PKA at heart levels.
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Affiliation(s)
- Pilar Almela
- Equip of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
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Rashid A, Hines M, Scherlag BJ, Yamanashi WS, Lovallo W. The effects of caffeine on the inducibility of atrial fibrillation. J Electrocardiol 2006; 39:421-5. [PMID: 16919674 PMCID: PMC2257921 DOI: 10.1016/j.jelectrocard.2005.12.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2005] [Accepted: 12/15/2005] [Indexed: 11/22/2022]
Abstract
INTRODUCTION There is widespread belief that caffeine consumption is linked to atrial arrhythmias; however, there is a relative lack of systematic evidence to support the assertion. The purpose of this study was to investigate whether caffeine, in doses equivalent to daily use in the general population, alter the propensity for atrial fibrillation (AF) in an experimental model comparing normal and simulated predisposition to AF. METHODS AND MATERIAL Caffeine (caffeine Na benzoate, 50:50 mixture) was administered intravenously at 1, 3, and 5 mg/kg doses in dogs producing serum levels of 2 to 4, 5 to 7, and 8 to 10 microg/mL. To simulate focal AF, premature stimulation from the right superior pulmonary vein was delivered at 2x, 4x, and 10x threshold at a rate of 180/min (S(1)-S(2) = 330 milliseconds) without and then with low-level stimulation of ganglionated plexi (GP) at the entrance of the right superior pulmonary vein. The window of vulnerability (WOV), a measure of the propensity for AF inducibility, was determined by the longest coupling interval of the premature beat (S(1)-S(2)) minus the shortest S(1)-S(2), which induced AF. The cumulative WOV is the sum of the individually determined WOV. RESULTS At each serum level of caffeine, the cumulative WOV was lower without rather than with GP stimulation compared with control. The cumulative WOV for both the stimulated, that is, predisposed to AF, and nonstimulated, that is, normal groups, exhibited a significantly lower average as compared with that exhibited by the control group (P <or= .003-.02). CONCLUSION These findings suggest that the presence of caffeine may result in an unexpected reduction in the propensity for AF in healthy individuals and in those with a predisposition for AF (enhanced AF inducibility caused by the stimulation of the GP).
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Affiliation(s)
- Abdul Rashid
- Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Mujahid Hines
- College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Benjamin J. Scherlag
- Cardiac Arrhythmia Research Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Corresponding author. E-mail address: (B.J. Scherlag)
| | - William S. Yamanashi
- Cardiac Arrhythmia Research Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - William Lovallo
- Department of Veterans Affairs Medical Center, Oklahoma City, OK 73104, USA
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Almela P, Cerezo M, Milanés MV, Laorden ML. Role of PKC in regulation of Fos and TH expression after naloxone induced morphine withdrawal in the heart. Naunyn Schmiedebergs Arch Pharmacol 2006; 372:374-82. [PMID: 16474935 DOI: 10.1007/s00210-006-0032-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2005] [Accepted: 12/19/2005] [Indexed: 11/29/2022]
Abstract
We previously demonstrated that morphine withdrawal induced hyperactivity of the heart by activation of noradrenergic pathways innervating the left and right ventricle, as evaluated by noradrenaline (NA) turnover and Fos expression. The present study was designed to investigate the role of protein kinase C (PKC) in this process, by estimating whether pharmacological inhibition of PKC would attenuate morphine withdrawal induced Fos expression and changes in tyrosine hydroxylase (TH) immunoreactivity levels and NA turnover in the left and right ventricle. Dependence on morphine was induced on day 8 by an injection of naloxone. Morphine withdrawal induced Fos expression and increased TH levels and NA turnover in the right and left ventricle. Infusion of calphostin C, a selective PKC inhibitor, did not modify the morphine withdrawal-induced increase in NA turnover and TH levels. However, this inhibitor produced a reduction in the morphine withdrawal-induced Fos expression. The results of the present study provide new information on the mechanisms that underlie morphine withdrawal-induced up-regulation of Fos expression in the heart and suggest that TH is not a target of PKC during morphine withdrawal at heart levels.
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Affiliation(s)
- Pilar Almela
- Equip of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
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18
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González-Cuello A, Milanés MV, Laorden ML. Increase of tyrosine hydroxylase levels and activity during morphine withdrawal in the heart. Eur J Pharmacol 2004; 506:119-28. [PMID: 15588731 DOI: 10.1016/j.ejphar.2004.11.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Accepted: 11/02/2004] [Indexed: 11/16/2022]
Abstract
Our previous studies have shown an enhanced activity of the noradrenergic pathways innervating the heart in rats withdrawn from morphine. However, the possible adaptive changes that can occur in these pathways during morphine dependence are not known. We studied the alterations in tyrosine hydroxylase (the rate-limiting enzyme in catecholamines biosynthesis) and tyrosine hydroxylase activity in the heart (right and left ventricle) during morphine withdrawal. In the same paradigm, we measured Fos expression as a marker of neuronal activation and the normetanephrine/noradrenaline ratio (an index of noradrenaline turnover). We evaluated the levels of tyrosine hydroxylase and Fos by quantitative Western blot analysis, and noradrenaline turnover using high-performance liquid chromatography (HPLC). Dependence on morphine was induced by a 7-day s.c. implantation of morphine pellets. Morphine withdrawal was precipitated on day 8 by an injection of naloxone (5 mg/kg s.c.). The results show a significant increase in tyrosine hydroxylase levels and activity in the right and left ventricle 30 or 90 min after naloxone precipitated withdrawal in parallel with an increase in noradrenaline turnover. Morphine withdrawal also induced an increase in the Fos expression, which indicates an activation of cardiac cellular activity. Our results suggest that an increase in tyrosine hydroxylase protein levels and tyrosine hydroxylase enzyme activity might contribute to the enhanced noradrenergic activity in the heart in response to morphine withdrawal.
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Affiliation(s)
- Ana González-Cuello
- Equip of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
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19
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González-Cuello A, Milanés MV, Castells MT, Laorden ML. Morphine withdrawal-induced c-fos expression in the heart: a peripheral mechanism. Eur J Pharmacol 2004; 487:117-24. [PMID: 15033383 DOI: 10.1016/j.ejphar.2004.01.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2003] [Revised: 12/03/2003] [Accepted: 01/21/2004] [Indexed: 11/23/2022]
Abstract
We previously demonstrated that hyperactivity of cardiac noradrenergic pathways observed during morphine withdrawal is mediated by peripheral mechanisms. In the present study, naloxone methiodide (quaternary derivative of naloxone that does not cross the blood-brain barrier) and naloxone were administered to morphine-dependent rats and Fos immunostaining was used as a reflection of neuronal activity. Dependence on morphine was induced by 7-day chronic subcutaneous (s.c.) implantation of six morphine pellets (75 mg). Morphine withdrawal was precipitated by administration of naloxone methiodide (5 mg/kg, s.c.) or naloxone (5 mg/kg, s.c.) on day 8. Using immunohistochemical staining of Fos, present results indicate that the administration of naloxone methiodide or naloxone to morphine-dependent rats induced marked Fos immunoreactivity within the cardiomyocyte nuclei. Moreover, Western blot analysis revealed a peak expression of c-fos in the right and left ventricles after naloxone methiodide- or naloxone-precipitated withdrawal. In addition, in the hypothalamic paraventricular nucleus (PVN), Fos expression was increased after naloxone-but not after naloxone methiodide-administration to morphine-dependent rats. These results suggest that the activation of c-fos expression observed during morphine withdrawal in the heart is due to intrinsic mechanisms outside the central nervous system (CNS).
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Affiliation(s)
- Ana González-Cuello
- Department of Cellular and Molecular Pharmacology, University School of Medicine, Murcia, Spain
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20
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Abstract
PURPOSE OF REVIEW Recent progress in understanding the role of the autonomic nervous system in the development of cardiac arrhythmias is reviewed. The focus is on the translation of basic principles of neural control of heart rhythm that have emerged from experimental studies to clinical applications. RECENT FINDINGS Recent studies have made significant strides in defining the function of intrinsic cardiac innervation and the importance of nerve sprouting in electrical remodeling. A recurring theme is that heterogeneity of sympathetic innervation in response to injury is highly arrhythmogenic. In addition, both sympathetic and parasympathetic influences on ion channel activity have been found to accentuate electrical heterogeneities and thus to contribute to arrhythmogenesis in the long QT and Brugada syndromes. In the clinic, heart rate variability continues to be a useful tool in delineating pathophysiologic changes that result from the progression of heart disease and the impact of diabetic neuropathy. Heart rate turbulence, a noninvasive indicator of baroreceptor sensitivity, has emerged as a simple, practical tool to assess risk for cardiovascular mortality in patients with ischemic heart disease and heart failure. Evidence of the proarrhythmic influence of behavioral stress has been further bolstered by defibrillator discharge studies and ambulatory ECG-based T-wave alternans measurement. SUMMARY The results of recent investigations underscore the importance of the autonomic influences as triggers of arrhythmia and provide important mechanistic insights into the ionic and cellular mechanisms involved.
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Affiliation(s)
- Richard L. Verrier
- From: Beth Israel Deaconess Medical Center, Harvard Medical School, Boston MA and
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21
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Arora RC, Cardinal R, Smith FM, Ardell JL, Dell'Italia LJ, Armour JA. Intrinsic cardiac nervous system in tachycardia induced heart failure. Am J Physiol Regul Integr Comp Physiol 2003; 285:R1212-23. [PMID: 12893651 DOI: 10.1152/ajpregu.00131.2003] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The purpose of this study was to test the hypothesis that early-stage heart failure differentially affects the intrinsic cardiac nervous system's capacity to regulate cardiac function. After 2 wk of rapid ventricular pacing in nine anesthetized canines, cardiac and right atrial neuronal function were evaluated in situ in response to enhanced cardiac sensory inputs, stimulation of extracardiac autonomic efferent neuronal inputs, and close coronary arterial administration of neurochemicals that included nicotine. Right atrial neuronal intracellular electrophysiological properties were then evaluated in vitro in response to synaptic activation and nicotine. Intrinsic cardiac nicotine-sensitive, neuronally induced cardiac responses were also evaluated in eight sham-operated, unpaced animals. Two weeks of rapid ventricular pacing reduced the cardiac index by 54%. Intrinsic cardiac neurons of paced hearts maintained their cardiac mechano- and chemosensory transduction properties in vivo. They also responded normally to sympathetic and parasympathetic preganglionic efferent neuronal inputs, as well as to locally administered alpha-or beta-adrenergic agonists or angiotensin II. The dose of nicotine needed to modify intrinsic cardiac neurons was 50 times greater in failure compared with normal preparations. That dose failed to alter monitored cardiovascular indexes in failing preparations. Phasic and accommodating neurons identified in vitro displayed altered intracellular membrane properties compared with control, including decreased membrane resistance, indicative of reduced excitability. Early-stage heart failure differentially affects the intrinsic cardiac nervous system's capacity to regulate cardiodynamics. While maintaining its capacity to transduce cardiac mechano- and chemosensory inputs, as well as inputs from extracardiac autonomic efferent neurons, intrinsic cardiac nicotine-sensitive, local-circuit neurons differentially remodel such that their capacity to influence cardiodynamics becomes obtunded.
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Affiliation(s)
- Rakesh C Arora
- Centre de Recherche, Hôpital du Sacré-coeur, 5400 Boulevard Gouin ouest, Montréal, QC, Canada H4J 1C5
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22
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Guzzetti S, Colombo A, Piccaluga E, Tagliabue L, Magatelli R, Cantoni G, Viecca M. Absence of clinical signs of cardiac denervation after percutaneous myocardial laser revascularization. Int J Cardiol 2003; 91:129-35. [PMID: 14559122 DOI: 10.1016/s0167-5273(02)00602-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Percutaneous myocardial revascularization with laser (PMR) is a catheter-based technique that has generated much interest in the treatment of patients with severe coronary artery disease. Several mechanisms have been proposed to explain the reported clinical benefits of this technique. Cardiac autonomic denervation is among these. METHODS We studied 32 consecutive patients with chronic severe angina not suitable for other revascularization approaches. Canadian Class Society (CCS) class clinical assessment, Naughton exercise stress test, and scintigraphic myocardial perfusion were evaluated before and 1 and 6 months after PMR. Ewing's autonomic tests, heart rate variability (HRV), and plasmatic catecholamines were assessed before revascularization in non-diabetic and diabetic patients and repeated 1 month after PMR in 13 non-diabetics. A psychological test was carried out before PMR to evaluate the attitude towards this new procedure. RESULTS All the markers of autonomic cardiac control were unmodified after the procedure. Moreover, scintigraphic perfusion measured in the lasered areas was similar before and after the procedure. On the other hand, the clinical conditions significantly improved (CCS class from 3+/-0.8 to 1.9+/-0.9 at 1 month, P<0.01) and the exercise-related ischemic threshold was significantly better (from 311+/-28 to 453+/-51 s, P<0.05). The patients with a psychologically 'positive' expectation for this new procedure had results comparable to those with a 'negative' expectation. CONCLUSIONS PMR improves symptoms in patients with end-stage coronary artery disease in the absence of any detectable clinical sign of heart denervation.
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Affiliation(s)
- Stefano Guzzetti
- Medicina Interna II, Ospedale L. Sacco, via GB Grassi 74, Milan 20157, Italy.
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Smith FM, McGuirt AS, Leger J, Armour JA, Ardell JL. Effects of chronic cardiac decentralization on functional properties of canine intracardiac neurons in vitro. Am J Physiol Regul Integr Comp Physiol 2001; 281:R1474-82. [PMID: 11641118 DOI: 10.1152/ajpregu.2001.281.5.r1474] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Although intrinsic cardiac neurons display ongoing activity after chronic interruption of extrinsic autonomic inputs to the heart, the effects of decentralization on individual neurons remain unknown. The objective of this study was to determine the effects of chronic (3-4 wk) surgical decentralization on intracellular properties of, and neurotransmission among, neurons contained within the canine intrinsic right atrial ganglionated plexus in vitro. Properties of neurons from decentralized hearts were compared with those of neurons from sham-operated hearts (controls). Two populations of neurons were identified by their firing behavior in response to intracellular current injection. Fifty-nine percent of control neurons and 72% of decentralized neurons were phasic (discharged one action potential on excitation). Forty-one percent of control neurons and 27% of decentralized neurons were accommodating (multiple discharge with decrementing frequency). After chronic decentralization, input resistance of phasic neurons increased, whereas the duration of afterhyperpolarization of accommodating neurons decreased. Postsynaptic responses to interganglionic nerve stimulation were evoked in 89% of control neurons and 83% of decentralized neurons; the majority of these responses involved nicotinic receptors. These results show that, after chronic decentralization, intrinsic cardiac neurons 1) undergo changes in membrane properties that may lead to increased excitability while 2) maintaining synaptic neurotransmission within the intrinsic cardiac ganglionated plexus.
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Affiliation(s)
- F M Smith
- Department of Anatomy and Neurobiology, Dalhousie University, Halifax, Nova Scotia B3H 4H7, Canada.
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Mukaddam-Daher S, Yin YL, Roy J, Gutkowska J, Cardinal R. Negative inotropic and chronotropic effects of oxytocin. Hypertension 2001; 38:292-6. [PMID: 11509492 DOI: 10.1161/01.hyp.38.2.292] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
We have previously shown that oxytocin receptors are present in the heart and that perfusion of isolated rat hearts with oxytocin results in decreased cardiac flow rate and bradycardia. The mechanisms involved in the negative inotropic and chronotropic effects of oxytocin were investigated in isolated dog right atria in the absence of central mechanisms. Perfusion of atria through the sinus node artery with 10(-6) mol/L oxytocin over 5 minutes (8 mL/min) significantly decreased both beating rate (-14.7+/-4.9% of basal levels, n=5, P<0.004) and force of contraction (-52.4+/-9.1% of basal levels, n=5, P<0.001). Co-perfusion with 10(-6) mol/L oxytocin receptor antagonist (n=3) completely inhibited the effects of oxytocin on frequency (P<0.04) and force of contraction (P<0.004), indicating receptor specificity. The effects of oxytocin were also totally inhibited by co-perfusion with 5x10(-8) mol/L tetrodotoxin (P<0.02) or 10(-6) mol/L atropine (P<0.03) but not by 10(-6) mol/L hexamethonium, which implies that these effects are neurally mediated, primarily by intrinsic parasympathetic postganglionic neurons. Co-perfusion with 10(-6) mol/L NO synthase inhibitor (L-NAME) significantly inhibited oxytocin effects on both beating rate (-1.85+/-1.27% versus -14.7+/-4.9% in oxytocin alone, P<0.05) and force of contraction (-24.9+/-4.4% versus -52.4+/-9.1% in oxytocin alone, n=4, P<0.04). The effect of oxytocin on contractility was further inhibited by L-NAME at 10(-4) mol/L (-8.1+/-1.8%, P<0.01). These studies imply that the negative inotropic and chronotropic effects of oxytocin are mediated by cardiac oxytocin receptors and that intrinsic cardiac cholinergic neurons and NO are involved in these actions.
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Affiliation(s)
- S Mukaddam-Daher
- Laboratory of Cardiovascular Biochemistry, Centre Hospitalier de L'Université de Montréal Research Center, Pavilion Hotel-Dieu, Montreal, Canada.
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25
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Abstract
The properties of the postganglionic sympathetic neurones supplying the heart and arising in the stellate and adjacent paravertebral ganglia of various species are discussed with respect to their location, morphology, synaptic input and membrane characteristics. Results from our laboratory on the morphology of rat stellate neurones projecting to the heart were obtained either by intracellular injection of hexammine cobaltic (III) chloride or by retrograde labelling of cells using cobalt-lysine complex. Intracellular recordings were made from cells using electrodes filled either with potassium chloride plus hexammine cobaltic chloride or potassium acetate. Neurones which projected axons into cardiac nerve branches arising from the stellate ganglion were termed putative cardiac neurones, because of the possibility that some supply pulmonary targets. Putative cardiac neurones had unbranched axons and were ovoid or polygonal in shape, but showed considerable variation in soma size and in the complexity of dendritic trees. The mean two-dimensional surface area was 463 microns2 and the mean number of primary dendrites was seven. Other studies have found that the morphology of rat stellate ganglion neurones is similar to that of superior cervical ganglion cells. However, in strains of rat displaying spontaneous hypertension, dendritic length may be increased. Histochemical studies do not, as yet, seem to have demonstrated a distinctive neurochemical profile for stellate cardiac neurones, but various types of peptide-containing intraganglionic nerve fibres have been identified in the guinea pig. In our electrophysiological studies, putative cardiac neurones were found to receive a complex presynaptic input arising from the caudal sympathetic trunk and from T1 and T2 thoracic rami. In addition, 16% of cardiac neurones received a synaptic input from the cardiac nerve. The properties of postganglionic parasympathetic neurones distributed in the cardiac plexus and termed intrinsic cardiac neurones are discussed, including the results of studies on cultures of these neurones.
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MESH Headings
- Animals
- Axons/physiology
- Cell Membrane/chemistry
- Cell Membrane/physiology
- Dendrites/physiology
- Electric Conductivity
- Ganglia, Autonomic/anatomy & histology
- Ganglia, Autonomic/cytology
- Ganglia, Autonomic/physiology
- Ganglia, Parasympathetic/anatomy & histology
- Ganglia, Parasympathetic/cytology
- Ganglia, Parasympathetic/physiology
- Ganglia, Sympathetic/anatomy & histology
- Ganglia, Sympathetic/cytology
- Ganglia, Sympathetic/physiology
- Heart/innervation
- Immunohistochemistry
- Rats
- Rats, Wistar
- Stellate Ganglion/anatomy & histology
- Stellate Ganglion/cytology
- Stellate Ganglion/physiology
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Affiliation(s)
- D Wallis
- School of Molecular and Medical Biosciences, University of Wales College of Cardiff, Wales
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Gatti PJ, Johnson TA, Massari VJ. Can neurons in the nucleus ambiguus selectively regulate cardiac rate and atrio-ventricular conduction? JOURNAL OF THE AUTONOMIC NERVOUS SYSTEM 1996; 57:123-7. [PMID: 8867095 DOI: 10.1016/0165-1838(95)00104-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Previous anatomic data have described the distribution of presumptive negative chronotropic and negative dromotropic neurons in the ventro-lateral nucleus ambiguus (NA-VL) following injections of retrograde tracers into physiologically selective parasympathetic intracardiac ganglia. Negative dromotropic neurons were preferentially distributed in the rostral NA-VL (rNA-VL). Negative chronotropic neurons were preferentially distributed in the caudal NA-VL (cNA-VL). Significant numbers of both types of cardio-inhibitory neurons were observed to overlap in an intermediate level of the NA-VL (iNA-VL). In the present report, we have examined the effects of microinjections of the excitatory amino-acid glutamate (GLU) into the cNA-VL and iNA-VL on cardiac rate and AV conduction while recording the electrocardiogram in paced and non-paced cat hearts. The data indicate that: (i) excitation of neurons in the cNA-VL causes a 58 +/- 17% reduction in cardiac rate, without influencing AV conduction; and (ii) excitation of neurons in the iNA-VL causes both a reduction in heart rate (68 +/- 12%) and a decrease in the rate of AV conduction (38 +/- 7%). These physiological results support the anatomical inference that neurons in the cNA-VL that are retrogradely labeled from physiologically selective parasympathetic intracardiac ganglia selectively exhibit negative chronotropic properties. Furthermore, the data indicate that there is a longitudinal cardiotopic organization of both negative chronotropic and negative dromotropic neurons in the NA-VL. This CNS organization mirrors the peripheral organization of functionally selective cardiac components of the vagus nerve. Finally, the data are consistent with the hypothesis that anatomically separated and functionally selective parasympathetic preganglionic vagal motoneurons in the NA independently control cardiac rate and AV conduction.
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Affiliation(s)
- P J Gatti
- Department of Pharmacology, Howard University College of Medicine, Washington, DC 20059, USA
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27
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Massari VJ, Johnson TA, Gatti PJ. Cardiotopic organization of the nucleus ambiguus? An anatomical and physiological analysis of neurons regulating atrioventricular conduction. Brain Res 1995; 679:227-40. [PMID: 7543355 DOI: 10.1016/0006-8993(95)00227-h] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Previous data indicate that there are anatomically segregated and physiologically independent parasympathetic postganglionic vagal motoneurons on the surface of the heart which are capable of selective control of sinoatrial rate, atrioventricular conduction and atrial contractility. We have injected a retrograde tracer into the cardiac ganglion which selectively regulates atrioventricular conduction (the AV ganglion). Medullary tissues were processed for the histochemical detection of retrogradely labeled neurons by light and electron microscopic methods. Negative dromotropic retrogradely labeled cells were found in a long column in the ventrolateral nucleus ambiguus (NA-VL), which enlarged somewhat at the level of the area postrema, but reached its largest size rostral to the area postrema in an area termed the rostral ventrolateral nucleus ambiguus (rNA-VL). Three times as many cells were observed in the left rNA-VL as compared to the right (P < 0.025). Retrogradely labeled cells were also consistantly observed in the dorsal motor nucleus of the vagus (DMV). The DMV contained one third as many cells as the NA-VL. The right DMV contained twice as many cells as the left (P < 0.05). These data are consistent with physiological evidence that suggests that the left vagus nerve is dominant in the regulation of AV conduction, but that the right vagus nerve is also influential. While recording the electrocardiogram in paced and non-paced hearts, L-glutamate (GLU) was microinjected into the rNA-VL. Microinjections of GLU caused a 76% decrease in the rate of atrioventricular (AV) conduction (P < 0.05) and occasional second degree heart block, without changing heart rate. The effects of GLU were abolished by ipsilateral cervical vagotomy. These physiological data therefore support the anatomical inference that CNS neurons that are retrogradely labeled from the AV ganglion selectively exhibit negative dromotropic properties. Retrogradely labeled negative dromotropic neurons displayed a round nucleus with ample cytoplasm, abundant rough endoplasmic reticulum and the presence of distinctive somatic and dendritic spines. These neurons received synapses from afferent terminals containing small pleomorphic vesicles and large dense core vesicles. These terminals made both asymmetric and symmetric contacts with negative dromotropic dendrites and perikarya, respectively. In conclusion, the data presented indicate that there is a cardiotopic organization of ultrastructurally distinctive negative dromotropic neurons in the NA-VL. This central organization of parasympathetic preganglionic vagal motoneurons mirrors the functional organization of cardioinhibitory postganglionic neurons of the peripheral vagus nerve. These data are further discussed in comparison to a recent report on the light microscopic distribution and ultrastructural characteristics of negative chronotropic neurons in the NA-VL42.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- V J Massari
- Department of Pharmacology, Howard University College of Medicine, Washington, DC 20059, USA
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28
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Wolf S. Effects of transient coronary artery occlusion on canine intrinsic cardiac neuronal activity. INTEGRATIVE PHYSIOLOGICAL AND BEHAVIORAL SCIENCE : THE OFFICIAL JOURNAL OF THE PAVLOVIAN SOCIETY 1993; 28:3-4. [PMID: 8476740 DOI: 10.1007/bf02691194] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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