Cardio-Respiratory Control in Vertebrates (eBook)

Preface 5
Contents 6
Contributors 8
Overview of the Respiratory System 12
References 13
Part I Control of Respiration in Aquatic Vertebrates 14
Gas Transport and Gill Function in Water-Breathing Fish 15
1 Introduction 15
2 Blood Oxygen Transport and Transfer Across the Gill 16
2.1 Carriage of O2 in the Blood 16
2.1.1 Haematocrit 16
2.1.2 Haemoglobin O2 Binding Affinity 18
2.2 O2 Transfer Across the Gill 19
3 Blood Carbon Dioxide Transport and Transfer Across the Gill 21
3.1 Carriage of CO2 in the Blood 21
3.2 Molecular Mechanisms Underlying CO2 Transportand Transfer in Teleost Fish 22
3.3 Alternative Strategies of CO2 Transport and Excretion 25
4 Sensing of Respiratory Gases at the Gill 27
4.1 Downstream Responses Associated with Chemoreceptor Activation 27
4.2 Location and Orientation of Branchial Chemoreceptors 28
4.3 Cellular Mechanisms of O2 and CO2 Sensing 29
4.4 Chemoreceptor Plasticity 29
5 Ammonia Excretion 30
5.1 Toxicity 31
5.2 Ammonia Excretion Pathways 32
5.2.1 Passive Diffusion of NH3 32
5.2.2 Passive Diffusion of NH4+ 34
5.2.3 Na+/NH4+ Exchange 35
5.2.4 Active Excretion of Tamm 35
5.3 Problems with the Models 36
5.3.1 Rh Proteins 36
References 38
Patterns of Acid–Base Regulation During Exposureto Hypercarbia in Fishes 53
1 Introduction 54
2 Regulation of pH in the Blood and Extracellular Space 54
3 Environmental Hypercarbia 55
4 Acid–Base Compensation During Exposure to Hypercarbia 56
5 Limitations to Extracellular pH Compensation During Hypercapnia 60
6 Novel Patterns of pH Regulation in Response to Hypercarbia in Pleisiomorphic and Air-Breathing Fishes 62
6.1 Pacific Hagfish 62
6.2 Sturgeon 63
6.3 Air-Breathing Fish 65
7 Conclusions and Speculations 68
References 69
Buoyancy Control in Aquatic Vertebrates 74
1 Introduction 74
2 The Problem of Buoyancy 75
2.1 Hydrostatic Pressure 75
2.2 Volume of Low Density Buoyancy Devices 76
2.3 Energy Expenditure 77
3 Buoyancy Devices in Teleosts and Elasmobranchs 78
3.1 The Swimbladder 78
3.1.1 Mechanisms of Gas Deposition 80
3.1.2 Resorption of Gas 85
3.1.3 Control of Swimbladder Inflation 86
3.1.4 Swimbladder Function During Vertical Migrations 87
3.2 Lipid Accumulation 88
3.2.1 Lipid-Filled Swimbladders 90
3.2.2 Lipid Accumulation in the Liver 91
3.2.3 Lipids in Bones and Other Tissues 92
3.2.4 Lipid Droplets in Eggs and Larvae 93
3.3 Watery Tissues 93
3.4 Hydrodynamic Lift 94
4 Diving Reptiles and Birds 96
5 Buoyancy in Mammals 97
6 Conclusions 100
References 100
Gas Exchange and Control of Respiration in Air-Breathing Teleost Fish 108
1 Introduction 108
1.1 Air and Water as Respiratory Media 108
1.2 Evolution of the Atmosphere 109
1.3 Hypoxia and Hypercarbia 110
1.4 Gill Function and O2 Extraction 111
1.5 Air-Breathing Organs and Their Function 112
1.6 Polypterus senegalus (Polypteridae) 113
1.7 The gars (Lepisosteus sp.) and the bowfins (Amia calva) Amiidae, Amiiformes 113
1.8 Channa argus (Channidae) 114
1.9 Hypostomus sp. (Loricariidae) 115
1.10 Clarias sp. (Clariidae) 117
1.11 Oxygen and CO2/H+ Receptors 119
1.12 The Air-Breathing Descendents of the Sarcopterygians 121
References 123
Effects of Temperature on Cardiac Function in Teleost Fish 129
1 Introduction 129
1.1 Temperature as a Controlling and Limiting Factor 130
2 Cardiac Output, Heart Rate, and Stroke Volume 132
2.1 Heart Pacemaker 141
2.2 ECG 143
3 In vitro Cardiac Performance 148
References 162
Physiological Evidence Indicates Lungfish as a Sister Group to the Land Vertebrates 169
1 Introduction 169
2 How Advanced is the Lungfish Lung? 171
3 Regulation of Acid–Base Status and Oxygen Levels 172
4 Respiratory Control in Lungfish Compared to Amphibians and Other Land Vertebrates 173
5 Focus on the South American Lungfish L. paradoxa 173
6 Focus on the African Lungfish Protopterus sp 177
7 Focus on the Australian Lungfish Neoceratodus Forsteri 179
8 Aestivation 179
References 181
Aestivation in Amphibians, Reptiles, and Lungfish 186
1 Introduction to Aestivation 186
1.1 Metabolic Downregulation and Aestivation in Anuran Amphibians 187
1.2 Dormancy in Reptiles 189
1.3 Dormancy in Lungfish 190
References 194
Part II Evolution of Pulmonary Mechanics and Respiratory Control 197
Trade-offs in the Evolution of the Respiratory Apparatus of Chordates 198
1 Introduction 198
2 Aquatic Water Breathers: Interaction of Respiratory, Cardiovascular, Locomotor and Nutritional Faculties 199
3 Aquatic Air Breathers 201
4 Terrestrial Air Breathers 202
4.1 Structures that Increase the Efficiency of Inspiration 203
4.2 Special (Apomorphic) Inspiratory Muscles 204
References 206
Environmental Selection Pressures Shaping the Pulmonary Surfactant System of Adult and Developing Lungs 210
1 Introduction 210
1.1 The Structure and Composition of the Pulmonary Surfactant System 211
1.2 The Function of the Pulmonary Surfactant System 213
1.3 The Control of the Pulmonary Surfactant System 214
1.4 Environmental Influences on the Surfactant System 215
2 Temperature 216
2.1 Temperature: A Selection Force for the Evolution ofSurfactant Lipid Composition across the Vertebrates 216
2.2 Temperature: A Selection Force for Acute Changesin Surfactant Composition, Structure and FunctionWithin Individuals 218
2.2.1 Surfactant Lipid Composition 218
2.2.2 Surfactant Protein Composition 220
2.2.3 Surfactant Protein Structure and Function 220
2.2.4 Surfactant Biophysical Function During Activity, Torpor and Arousal 221
2.2.5 Surfactant Film Structure 223
3 Pressure 224
3.1 Selection at the Molecular Level 226
3.2 Selection at the Compositional Level 228
3.2.1 Phospholipids and Cholesterol 228
3.2.2 Surfactant Proteins 229
3.3 Selection at the Functional Level 230
4 Hypoxia 231
4.1 Hypoxia and Altitude: Effects on the Adult Pulmonary Surfactant System 232
4.2 Fetal Hypoxia and Growth Restriction: Effectson the Pulmonary Surfactant System in Mammals 232
4.3 Fetal Hypoxia: Effects on the Pulmonary Surfactant Systemin Non-mammals 235
5 Conclusions and Future Directions 237
References 238
Midbrain Structures and Control of Ventilation in Amphibians 245
1 Introduction 245
2 Lesion Studies 247
2.1 Basal Respiratory Drive 247
2.2 Responses to Hypoxia 248
2.3 Responses to Hypercarbia 250
3 Putative Mediators Within the NI 251
3.1 Glutamate 251
3.2 Nitric Oxide 252
4 Locus Coeruleus 254
4.1 Basal Respiratory Drive 255
4.2 Responses to Hypercapnia 256
5 Final Remarks and Perspectives 258
References 260
Comparative Aspects of Hypoxia Tolerance of the Ectothermic Vertebrate Heart 266
1 Introduction 266
2 Comparative Hypoxia Tolerance of Cardiac Function 268
3 Cellular Energy Metabolism During Hypoxia/Anoxia 269
3.1 Metabolic Depression of the Whole Animal and the Heart 270
3.2 Aerobic Metabolism and Hypoxia 272
3.3 Enzyme Complement and the Relation Between Contractility and Energy State 273
4 Cellular Energy State and Contractile Force 275
5 Cardiac Excitation–Contraction (E, C) Coupling 277
6 Factors Influencing Cardiac Contractility During Anoxia 279
6.1 Acidosis 280
6.2 Hyperkalemia 280
6.3 Regulation of Hypoxic Contractility by Adrenaline and Ca2+ 281
7 Conclusion 282
References 282
Control of the Heart and of Cardiorespiratory Interactions in Ectothermic Vertebrates 288
1 Introduction 288
2 Efferent Innervation of the Vertebrate Heart 291
2.1 Elasmobranchs 292
2.2 Teleosts 294
2.3 Air-breathing Fish 296
2.4 Amphibians 296
2.5 Reptiles 297
3 Cardiorespiratory Interactions 299
3.1 Fish 299
3.2 Air-Breathing Fish 300
3.3 Amphibians 301
3.4 Reptiles 303
4 The Neural Basis of Cardiorespiratory Interactions 305
5 Fish 306
6 Elasmobranchs 306
7 Teleosts 307
8 Amphibians 308
9 Reptiles 309
10 Mechanisms of Phasic Vagal Control of the Heart 312
References 313
The Endocrine–Paracrine Control of the Cardiovascular System 319
1 Introduction 320
2 Basic Cold-Blooded Vertebrate Heart 321
3 Catecholamines 323
3.1 Cardiac Catecholamines 323
3.2 Autocrine/Paracrine Cardiac Effects of Catecholamines 324
3.3 Cardiotoxic Effects of Catecholamines 330
4 Natriuretic Peptides 331
4.1 Production and Release of Natriuretic Peptides 332
4.2 Natriuretic Peptide Receptor System 335
4.3 Cardiovascular Actions of Natriuretic Peptides 336
4.3.1 Cardiac Actions 336
4.3.2 Vascular Actions 338
4.3.3 Interactions with CAs 339
5 Chromogranin-A 340
5.1 The CgA-Derived Vasostatins 343
5.1.1 Action Mechanism/s of VSs 344
5.2 Catestatin 345
6 The Renin–Angiotensin-System 346
6.1 AngII Receptor System 349
6.2 AngII Cardiovascular Actions 351
7 Other Cardiac Endocrine/Paracrine/Autocrine Substances 354
8 A Major Autocrine/Paracrine Sensor-Integrator:The NOS–NO System 358
9 Concluding Remarks 360
References 361
Stoking the Brightest Fires of Life Among Vertebrates 382
1 Introduction 382
2 Pathways of Fuel Oxidation 383
3 Metabolic Rates During Flight 385
4 The Supply of Oxygen 387
5 Fuel Use During Flight: The Sucrose Oxidation Cascade 388
6 In Vitro, In Vivo and Beyond 391
7 Concluding Remarks 392
References 393
Part III Respiratory Physiology of Birds: Metabolic Control 396
Prenatal Development of Cardiovascular Regulation in Avian Species 397
1 Introduction 398
2 Ontogeny of the Control of the Heart Via the Autonomic Nervous System 400
2.1 Autonomic Innervation of the Heart 400
2.2 Cholinergic and Adrenergic Receptors on the Heart 401
3 Ontogeny of the Control of Vascular Contractility 402
3.1 Developmental Changes in the Mechanisms Controlling Vascular Reactivity 402
3.2 Adrenergic Receptors on the Chicken Vasculature 403
3.3 Cholinergic Receptors and the Endothelial Controlof Vascular Reactivity 404
3.4 Vascular Reactivity of the Ductus Arteriosus 406
3.5 Oxygen Sensing in Chicken Fetal Vessels 408
4 Functional Integration of Autonomic Cardiovascular Regulation 410
4.1 Ontogeny of Afferent Pathways 410
4.2 Onset of Tonic Control of the Heart 412
4.3 Onset of Tonic Control of the Vasculature 413
4.4 Maturation of Baroreflex Regulation 414
5 Effects of Humoral and Local Effectors: Angiotensin, Endothelin-1 and Natriuretic Peptides 417
References 419
Control of Breathing in Birds: Implications for High-Altitude Flight 428
1 Introduction 429
2 Ventilatory Responses to Exercise 430
3 Ventilatory Responses to Decreasing O2 432
4 Ventilatory Responses to Changing CO2/pH 434
5 Control of Breathing and Adaptation to High Altitude 437
6 Genetic Basis for Physiological Evolution 439
7 Conclusions 440
References 441
Part IV Mammalian and Human Physiology 448
Peripheral Chemoreceptors in Mammals: Structure, Function and Transduction 449
1 Introduction 449
2 Characteristics of Peripheral Chemoreceptor Tissue 450
2.1 Anatomical Distribution of Chemoreceptor Tissue 450
2.2 Cellular Constituents of Chemoreceptor Tissue 452
2.3 Blood Flow 453
3 Natural Stimuli of Peripheral Chemoreceptors 454
3.1 Hypoxia 455
3.1.1 Oxygen Tension or Content? 456
3.2 Hypercapnia and Acidosis 458
3.3 Stimulus Interaction 459
3.4 Other Non-Hypoxic Stimuli: Is the Carotid Body a Glucosensor? 460
4 Mechanism of Hypoxia Chemotransduction 462
4.1 O2 Sensitive K Channels 462
4.2 Protein Sensors 463
4.2.1 AMPK 464
4.2.2 Haem Oxygenase 464
5 Conclusions 465
References 466
Central Chemosensitivity in Mammals 472
1 Introduction 472
2 Organismal Chemosensitive Responsesto Environmental or Metabolic Stimuli 473
3 Altered Chemosensitivity in Disease 475
4 Development of the Organismal ChemosensitiveResponse 476
5 Central Chemosensitivity 476
6 Multiple Chemosensitive Regions in the Brainstem? 477
7 Development of Central Chemoreception 481
8 Central Vs Peripheral Chemoreception 483
9 Cellular Chemosensitive Signaling 484
10 Summary 489
References 489
Human Exercise Physiology 498
1 Introduction 498
2 Skeletal Muscles 499
3 Metabolic Demand 500
3.1 Metabolic Rate 501
4 Static and Dynamic Work 503
5 Energy Requirements and Cardiorespiratory Limitations 503
5.1 Aerobic Metabolism 504
5.2 Anaerobic Metabolism 506
6 Endocrine and Metabolic Responses 506
6.1 Blood Glucose 507
7 Ventilation 507
7.1 Breathing Pattern 508
7.2 Diffusing Capacity 509
7.3 Transport of O2 509
7.4 Haemoglobin 512
8 Blood Lactate 513
8.1 Lactate Threshold 514
9 The Heart Rate Response 514
9.1 Blood Volume and Cardiac Preload 515
9.2 Starling's Law of the Heart 515
9.3 Cardiac Output 516
9.4 The Heart 518
9.5 Stroke Volume 519
9.6 Extreme Exercise 520
9.7 Cardiac Output 520
10 Blood Pressure 521
11 Regional Blood Flow 522
12 Peripheral Gas Exchange 523
13 Brain 525
13.1 Cerebral Blood Flow During Exercise 526
13.2 Cerebral Energy Metabolism 528
13.3 Brain Glycogen Metabolism 529
14 Diving Response 530
15 Altitude 531
16 Heat and Cold 532
17 Genetic Influence 532
18 Health 532
References 534
Index 536