Respiratory systems

@article{johansen1967respiratory,
    author = "Johansen, Kjell and Lenfant, Claude and Grigg, Gordon C",
    title = "Respiratory control in the lungfish, Neoceratodus forsteri (krefft)",
    year = "1967",
    journal = "Comparative Biochemistry and Physiology",
    url = "https://doi.org/10.1016/0010-406x(67)90057-6",
    doi = "10.1016/0010-406x(67)90057-6",
    number = "3",
    pages = "835-854",
    volume = "20"
}

@misc{johansen1967respiratory1,
    author = "Johansen, K. and Lenfant, C. and Grigg, G. C",
    title = "Respiratory control in the lungfish",
    year = "1967",
    howpublished = "Comparative Biochemistry and Physiology, v. 20, p. 835-854",
    note = "talkorigins\_source = {true}; raw\_reference = {Johansen, K., Lenfant, C., and Grigg, G. C., 1967, Respiratory control in the lungfish: Comparative Biochemistry and Physiology, v. 20, p. 835-854.}"
}

The respiratory control in land vertebrates (Tetrapoda) is mainly linked to regulation of acid-base status, which involves peripheral and central chemoreceptors. The lungfish (Dipnoi) might constitute the sister group of all land vertebrates (Tetrapoda) and possess a combination of real lungs and reduced gills. In this context, we evaluated the possible presence of central respiratory chemoreceptors in the South American Lungfish, Lepidosiren paradoxa. Pulmonary ventilation and respiratory frequency increased significantly with reductions of CSF pH by means of mock CSF solutions. This suggests that Lepidosiren possess central acid-base receptors.

@article{doi101002jez1083,
    author = "Sanchez, A P and Hoffmann, A and Rantin, F T and Glass, M L",
    title = "Relationship between cerebro-spinal fluid pH and pulmonary ventilation of the South American lungfish, Lepidosiren paradoxa (Fitz.).",
    year = "2001",
    journal = "The Journal of experimental zoology",
    abstract = "The respiratory control in land vertebrates (Tetrapoda) is mainly linked to regulation of acid-base status, which involves peripheral and central chemoreceptors. The lungfish (Dipnoi) might constitute the sister group of all land vertebrates (Tetrapoda) and possess a combination of real lungs and reduced gills. In this context, we evaluated the possible presence of central respiratory chemoreceptors in the South American Lungfish, Lepidosiren paradoxa. Pulmonary ventilation and respiratory frequency increased significantly with reductions of CSF pH by means of mock CSF solutions. This suggests that Lepidosiren possess central acid-base receptors.",
    url = "https://pubmed.ncbi.nlm.nih.gov/11550190/",
    doi = "10.1002/jez.1083",
    pmid = "11550190"
}

@article{crossref2002control,
    title = "Control and Modulation of Respiratory Systems",
    year = "2002",
    journal = "The Journal of Physiology",
    url = "https://doi.org/10.1111/j.1469-7793.2002.tb00400.x",
    doi = "10.1111/j.1469-7793.2002.tb00400.x",
    number = "suppl",
    volume = "543"
}

Lungfish represent a probable sister group to the land vertebrates. Lungfish and tetrapods share features of respiratory control, including central, peripheral and intrapulmonary CO(2) receptors. We investigated whether or not central chemoreceptors in the lungfish, L. paradoxa, are stimulated by CO(2) and/or pH. Ventilation was measured by pneumotachography for diving animals. The fourth cerebral ventricle was equipped with two catheters for superfusion. Initially, two control groups were compared: (1) catheterized animals with no superfusion and (2) animals superfused with mock CSF solutions at pH = 7.45; PCO(2) = 21 mmHg. The two groups had virtually the same ventilation of about 40 ml BTPS kg(-1) h(-1) (P > 0.05). Next, PCO(2) was increased from 21 to 42 mmHg, while pH(CSF) was kept at 7.45, which increased ventilation from 40 to 75 ml BTPS kg(-1) h(-1). Conversely, a decrease of pH(CSF) from 7.45 to 7.20 (PCO(2) = 21 mmHg) increased ventilation to 111 ml BTPS kg(-1) h(-1). Further decreases of pH(CSF) had little effect on ventilation, and the combination of pH(CSF) = 7.10 and PCO(2) = 42 mmHg reduced ventilation to 63 ml BTPS kg(-1) h(-1).

@article{doi101007s003600070151x,
    author = "Amin-Naves, J and Giusti, H and Hoffmann, A and Glass, M L",
    title = "Central ventilatory control in the South American lungfish, Lepidosiren paradoxa: contributions of pH and CO(2).",
    year = "2007",
    journal = "Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology",
    abstract = "Lungfish represent a probable sister group to the land vertebrates. Lungfish and tetrapods share features of respiratory control, including central, peripheral and intrapulmonary CO(2) receptors. We investigated whether or not central chemoreceptors in the lungfish, L. paradoxa, are stimulated by CO(2) and/or pH. Ventilation was measured by pneumotachography for diving animals. The fourth cerebral ventricle was equipped with two catheters for superfusion. Initially, two control groups were compared: (1) catheterized animals with no superfusion and (2) animals superfused with mock CSF solutions at pH = 7.45; PCO(2) = 21 mmHg. The two groups had virtually the same ventilation of about 40 ml BTPS kg(-1) h(-1) (P > 0.05). Next, PCO(2) was increased from 21 to 42 mmHg, while pH(CSF) was kept at 7.45, which increased ventilation from 40 to 75 ml BTPS kg(-1) h(-1). Conversely, a decrease of pH(CSF) from 7.45 to 7.20 (PCO(2) = 21 mmHg) increased ventilation to 111 ml BTPS kg(-1) h(-1). Further decreases of pH(CSF) had little effect on ventilation, and the combination of pH(CSF) = 7.10 and PCO(2) = 42 mmHg reduced ventilation to 63 ml BTPS kg(-1) h(-1).",
    url = "https://pubmed.ncbi.nlm.nih.gov/17429654/",
    doi = "10.1007/s00360-007-0151-x",
    pmid = "17429654"
}

The present study has revealed that the lungfish has both structural and functional features of its system for physiological control of heart rate, previously considered solely mammalian, that together generate variability (HRV). Ultrastructural and electrophysiological investigation revealed that the nerves connecting the brain to the heart are myelinated, conferring rapid conduction velocities, comparable to mammalian fibers that generate instantaneous changes in heart rate at the onset of each air breath. These respiration-related changes in beat-to-beat cardiac intervals were detected by complex analysis of HRV and shown to maximize oxygen uptake per breath, a causal relationship never conclusively demonstrated in mammals. Cardiac vagal preganglionic neurons, responsible for controlling heart rate via the parasympathetic vagus nerve, were shown to have multiple locations, chiefly within the dorsal vagal motor nucleus that may enable interactive control of the circulatory and respiratory systems, similar to that described for tetrapods. The present illustration of an apparently highly evolved control system for HRV in a fish with a proven ancient lineage, based on paleontological, morphological, and recent genetic evidence, questions much of the anthropocentric thinking implied by some mammalian physiologists and encouraged by many psychobiologists. It is possible that some characteristics of mammalian respiratory sinus arrhythmia, for which functional roles have been sought, are evolutionary relics that had their physiological role defined in ancient representatives of the vertebrates with undivided circulatory systems.

@article{doi101126sciadvaaq0800,
    author = "Monteiro, Diana A and Taylor, Edwin W and Sartori, Marina R and Cruz, André L and Rantin, Francisco T and Leite, Cleo A C",
    title = "Cardiorespiratory interactions previously identified as mammalian are present in the primitive lungfish.",
    year = "2018",
    journal = "Science advances",
    abstract = "The present study has revealed that the lungfish has both structural and functional features of its system for physiological control of heart rate, previously considered solely mammalian, that together generate variability (HRV). Ultrastructural and electrophysiological investigation revealed that the nerves connecting the brain to the heart are myelinated, conferring rapid conduction velocities, comparable to mammalian fibers that generate instantaneous changes in heart rate at the onset of each air breath. These respiration-related changes in beat-to-beat cardiac intervals were detected by complex analysis of HRV and shown to maximize oxygen uptake per breath, a causal relationship never conclusively demonstrated in mammals. Cardiac vagal preganglionic neurons, responsible for controlling heart rate via the parasympathetic vagus nerve, were shown to have multiple locations, chiefly within the dorsal vagal motor nucleus that may enable interactive control of the circulatory and respiratory systems, similar to that described for tetrapods. The present illustration of an apparently highly evolved control system for HRV in a fish with a proven ancient lineage, based on paleontological, morphological, and recent genetic evidence, questions much of the anthropocentric thinking implied by some mammalian physiologists and encouraged by many psychobiologists. It is possible that some characteristics of mammalian respiratory sinus arrhythmia, for which functional roles have been sought, are evolutionary relics that had their physiological role defined in ancient representatives of the vertebrates with undivided circulatory systems.",
    url = "https://pmc.ncbi.nlm.nih.gov/articles/PMC5833999/",
    doi = "10.1126/sciadv.aaq0800",
    pmcid = "PMC5833999",
    pmid = "29507882"
}

The acid-base status is a tightly regulated physiological process, resulting from a balance of ions in the organism relevant to acid-base. The efficiency of the regulatory systems importantly determines the compensatory pH changes for a given disturb. Vertebrates minimize (or compensate) an acid-base disturb by general processes, which include ion transfer and/or PCO2 changes. Acid-base adjustment in fish is predominantly achieved by branchial exchange of acid-base relevant ions with correlated change in plasma HCO3- levels. Conversely, land vertebrates change blood PCO2 through ventilatory process and hence respiratory control of acid-base regulation plays an important role as a compensatory mechanism. Lungfishes (Dipnoi) have central position on vertebrate's evolution being considered as the sister group to the tetrapods. With an aquatic life mode, lungfish share similarities of respiratory function with tetrapods. This article reviews evidence showing that lungfish's respiratory system regulates acid-base status, like terrestrial ectothermic vertebrates. In the South American lungfish, Lepidosiren paradoxa, the presence of central CO2/pH chemoreceptors was unequivocally described. Also, the blood PCO2 and acid-base status are typical of a terrestrial vertebrate. These aspects are discussed under different environmental conditions that require respiratory acid-base adjustments, such as, exposure to hypercarbia, hypoxia, high temperature and aestivation. Interesting questions regarding the location and cell phenotype of CO2/pH central and peripheral chemoreceptors remain an open field to be explored in lungfish.

@article{doi101016jcbpa2019110533,
    author = "Nunan, Bruna L C Z and Silva, Ayla S and Wang, Tobias and da Silva, Glauber S F",
    title = "Respiratory control of acid-base status in lungfish.",
    year = "2019",
    journal = "Comparative biochemistry and physiology. Part A, Molecular \& integrative physiology",
    abstract = "The acid-base status is a tightly regulated physiological process, resulting from a balance of ions in the organism relevant to acid-base. The efficiency of the regulatory systems importantly determines the compensatory pH changes for a given disturb. Vertebrates minimize (or compensate) an acid-base disturb by general processes, which include ion transfer and/or PCO2 changes. Acid-base adjustment in fish is predominantly achieved by branchial exchange of acid-base relevant ions with correlated change in plasma HCO3- levels. Conversely, land vertebrates change blood PCO2 through ventilatory process and hence respiratory control of acid-base regulation plays an important role as a compensatory mechanism. Lungfishes (Dipnoi) have central position on vertebrate's evolution being considered as the sister group to the tetrapods. With an aquatic life mode, lungfish share similarities of respiratory function with tetrapods. This article reviews evidence showing that lungfish's respiratory system regulates acid-base status, like terrestrial ectothermic vertebrates. In the South American lungfish, Lepidosiren paradoxa, the presence of central CO2/pH chemoreceptors was unequivocally described. Also, the blood PCO2 and acid-base status are typical of a terrestrial vertebrate. These aspects are discussed under different environmental conditions that require respiratory acid-base adjustments, such as, exposure to hypercarbia, hypoxia, high temperature and aestivation. Interesting questions regarding the location and cell phenotype of CO2/pH central and peripheral chemoreceptors remain an open field to be explored in lungfish.",
    url = "https://pubmed.ncbi.nlm.nih.gov/31398391/",
    doi = "10.1016/j.cbpa.2019.110533",
    pmid = "31398391"
}

@article{hunnekens2020variablegain,
    author = "Hunnekens, Bram and Kamps, Sjors and Van De Wouw, Nathan",
    title = "Variable-Gain Control for Respiratory Systems",
    year = "2020",
    journal = "IEEE Transactions on Control Systems Technology",
    url = "https://doi.org/10.1109/tcst.2018.2871002",
    doi = "10.1109/tcst.2018.2871002",
    number = "1",
    pages = "163-171",
    volume = "28"
}

Mammals show clear changes in heart rate linked to lung ventilation, characterized as respiratory sinus arrhythmia (RSA). These changes are controlled in part by variations in the level of inhibitory control exerted on the heart by the parasympathetic arm of the autonomic nervous system (PNS). This originates from preganglionic neurons in the nucleus ambiguous that supply phasic, respiration-related activity to the cardiac branch of the vagus nerve, via myelinated, efferent fibres with rapid conduction velocities. An elaboration of these central mechanisms, under the control of a 'vagal system' has been endowed by psychologists with multiple functions concerned with 'social engagement' in mammals and, in particular, humans. Long-term study of cardiorespiratory interactions (CRI) in other major groups of vertebrates has established that they all show both tonic and phasic control of heart rate, imposed by the PNS. This derives centrally from neurones located in variously distributed nuclei, supplying the heart via fast-conducting, myelinated, efferent fibres. Water-breathing vertebrates, which include fishes and larval amphibians, typically show direct, 1:1 CRI between heart beats and gill ventilation, controlled from the dorsal vagal motor nucleus. In air-breathing, ectothermic vertebrates, including reptiles, amphibians and lungfish, CRI mirroring RSA have been shown to improve oxygen uptake during phasic ventilation by changes in perfusion of their respiratory organs, due to shunting of blood over across their undivided hearts. This system may constitute the evolutionary basis of that generating RSA in mammals, which now lacks a major physiological role in respiratory gas exchange, due to their completely divided systemic and pulmonary circulations.

@article{doi101016jbiopsycho2022108382,
    author = "Taylor, Edwin W and Wang, Tobias and Leite, Cleo A C",
    title = "An overview of the phylogeny of cardiorespiratory control in vertebrates with some reflections on the 'Polyvagal Theory'.",
    year = "2022",
    journal = "Biological psychology",
    abstract = "Mammals show clear changes in heart rate linked to lung ventilation, characterized as respiratory sinus arrhythmia (RSA). These changes are controlled in part by variations in the level of inhibitory control exerted on the heart by the parasympathetic arm of the autonomic nervous system (PNS). This originates from preganglionic neurons in the nucleus ambiguous that supply phasic, respiration-related activity to the cardiac branch of the vagus nerve, via myelinated, efferent fibres with rapid conduction velocities. An elaboration of these central mechanisms, under the control of a 'vagal system' has been endowed by psychologists with multiple functions concerned with 'social engagement' in mammals and, in particular, humans. Long-term study of cardiorespiratory interactions (CRI) in other major groups of vertebrates has established that they all show both tonic and phasic control of heart rate, imposed by the PNS. This derives centrally from neurones located in variously distributed nuclei, supplying the heart via fast-conducting, myelinated, efferent fibres. Water-breathing vertebrates, which include fishes and larval amphibians, typically show direct, 1:1 CRI between heart beats and gill ventilation, controlled from the dorsal vagal motor nucleus. In air-breathing, ectothermic vertebrates, including reptiles, amphibians and lungfish, CRI mirroring RSA have been shown to improve oxygen uptake during phasic ventilation by changes in perfusion of their respiratory organs, due to shunting of blood over across their undivided hearts. This system may constitute the evolutionary basis of that generating RSA in mammals, which now lacks a major physiological role in respiratory gas exchange, due to their completely divided systemic and pulmonary circulations.",
    url = "https://pubmed.ncbi.nlm.nih.gov/35777519/",
    doi = "10.1016/j.biopsycho.2022.108382",
    pmid = "35777519"
}