Branchial chemoreceptors mediate ventilatory responses to hypercapnic acidosis in channel catfish

Burleson, Mark L.; Smatresk, Neal J.

doi:10.1016/s1095-6433(00)00167-7

Cited by 66 publications

(35 citation statements)

References 33 publications

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“…2). Similar results were obtained in previous studies using adult fish (Burleson and Smatresk, 2000;Perry and McKendry, 2001;Perry and Reid, 2002;Gilmour et al, 2005;Abdallah et al, 2014). Thus the bulk of available evidence now suggests (although see Introduction) that the cardiorespiratory reflexes associated with acidic hypercapnia reflect the increase in P CO2 rather than the decrease in pH (Gilmour and Perry, 2007).…”

Section: Co 2 Versus Phsupporting

confidence: 82%

Cardiac responses to hypercapnia in larval zebrafish (Danio rerio): The links between CO2 chemoreception, catecholamines and carbonic anhydrase

Miller

Pollack

Bradshaw

et al. 2014

Journal of Experimental Biology

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The ontogeny of carbon dioxide (CO 2 ) sensing in zebrafish (Danio rerio) has not been examined. In this study, CO 2 -mediated increases in heart rate were used to gauge the capacity of zebrafish larvae to sense CO 2 . CO 2 is thought to be detected via neuroepithelial cells (NECs), which are homologous to mammalian carotid body glomus cells. Larvae at 5 days post-fertilization (d.p.f.) exhibited tachycardia when exposed for 30 min to 0.75% CO 2 (~5.63 mmHg); at 7 d.p.f., tachycardia was elicited by 0.5% CO 2 (~3.75 mmHg). Based on pharmacological evidence using β-adrenergic receptor (β-AR) antagonists, and confirmed by β 1 -AR translational gene knockdown using morpholinos, the reflex tachycardia accompanying hypercapnia was probably mediated by the interaction of catecholamines with cardiac β 1 receptors. Because the cardiac response to hypercapnia was abolished by the ganglionic blocker hexamethonium, it is probable that the reflex cardio-acceleration was mediated by catecholamines derived from sympathetic adrenergic neurons. Owing to its likely role in facilitating intracellular acidification during exposure to hypercapnia, it was hypothesized that carbonic anhydrase (CA) is involved in CO 2 sensing, and that inhibition of CA activity would blunt the downstream responses. Indeed, the cardiac response to hypercapnia (0.75% CO 2 ) was reduced in fish at 5 d.p.f. exposed to acetazolamide, a CA inhibitor, and in fish experiencing zCAc (CA2-like a) knockdown. Successful knockdown of zCAc was confirmed by CA activity measurements, western blotting and immunocytochemistry. Co-injection of embryos with zCAc morpholino and mRNA modified at the morpholino binding site restored normal levels of CA activity and protein levels, and restored (rescued) the usual cardiac responses to hypercapnia. These data, combined with the finding that zCAc is expressed in NECs located on the skin, suggest that the afferent limb of the CO 2 -induced cardiac reflex in zebrafish larvae is initiated by coetaneous CO 2 -sensing neuroepithelial cells.

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Section: Co 2 Versus Phsupporting

confidence: 82%

Cardiac responses to hypercapnia in larval zebrafish (Danio rerio): The links between CO2 chemoreception, catecholamines and carbonic anhydrase

Miller

Pollack

Bradshaw

et al. 2014

Journal of Experimental Biology

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“…JouveDuhamel and Truchot, 1983) but there is growing evidence for a direct ventilatory sensitivity to CO 2 , e.g. in teleosts and elasmobranchs (Burleson and Smatresk, 2000;McKendry et al, 2001). Thus, an acute stimulatory effect of hypercapnia on ventilation was demonstrated in European eel (McKenzie et al, 2002).…”

Section: Physiology Of Co 2 Effects: Molecular Tomentioning

confidence: 99%

Biological Impact of Elevated Ocean CO2 Concentrations: Lessons from Animal Physiology and Earth History

Pörtner

Langenbuch

Reipschläger

2004

Journal of Oceanography

616

460

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CO 2 currently accumulating in the atmosphere permeates into ocean surface layers, where it may impact on marine animals in addition to effects caused by global warming. At the same time, several countries are developing scenarios for the disposal of anthropogenic CO 2 in the worlds' oceans, especially the deep sea. Elevated CO 2 partial pressures (hypercapnia) will affect the physiology of water breathing animals, a phenomenon also considered in recent discussions of a role for CO 2 in mass extinction events in earth history. Our current knowledge of CO 2 effects ranges from effects of hypercapnia on acid-base regulation, calcification and growth to influences on respiration, energy turnover and mode of metabolism. The present paper attempts to evaluate critical processes and the thresholds beyond which these effects may become detrimental. CO 2 elicits acidosis not only in the water, but also in tissues and body fluids. Despite compensatory accumulation of bicarbonate, acid-base parameters (pH, bicarbonate and CO 2 levels) and ion levels reach new steady-state values, with specific, long-term effects on metabolic functions. Even though such processes may not be detrimental, they are expected to affect long-term growth and reproduction and may thus be harmful at population and species levels. Sensitivity is maximal in ommastrephid squid, which are characterized by a high metabolic rate and extremely pH-sensitive blood oxygen transport. Acute sensitivity is interpreted to be less in fish with intracellular blood pigments and higher capacities to compensate for CO 2 induced acid-base disturbances than invertebrates. Virtually nothing is known about the degree to which deep-sea fishes are affected by short or long term hypercapnia. Sensitivity to CO 2 is hypothesized to be related to the organizational level of an animal, its energy requirements and mode of life. Long-term effects expected at population and species levels are in line with recent considerations of a detrimental role of CO 2 during mass extinctions in the earth's history. Future research is needed in this area to evaluate critical effects of the various CO 2 disposal scenarios.

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“…Ocean acidification has received considerable attention as the main direct impact of increased ocean CO 2 , but other potential impacts of increased CO 2 have been overlooked. Indeed, increased CO 2 and lowered pH also affect respiratory processes by driving reduced binding affinity for oxygen in blood (Pörtner et al, 2004) and a direct ventilatory sensitivity to CO 2 (Burleson and Smatresk, 2000;McKendry et al, 2001). Hence, increased CO 2 also poses challenges to aerobic respiration, threatening marine life, an impact observed long ago on marine fishes in controlled laboratory conditions (Powers, 1922), and recently addressed by Brewer and Peltzer (2009) in a study of the changing ocean conditions.…”

Section: Introductionmentioning

confidence: 99%

Coupled CO<sub>2</sub> and O<sub>2</sub>-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System

et al. 2012

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Abstract. Carbon dioxide and coupled CO 2 and O 2 -driven compromises to marine life were examined along the Chilean sector of the Humboldt Current System, a particularly vulnerable hypoxic and upwelling area, applying the Respiration index (RI = log 10 pO 2 pCO 2 ) and the pH-dependent aragonite saturation ( ) to delineate the water masses where aerobic and calcifying organisms are stressed. As expected, there was a strong negative relationship between oxygen concentration and pH or pCO 2 in the studied area, with the subsurface hypoxic Equatorial Subsurface Waters extending from 100 m to about 300 m depth and supporting elevated pCO 2 values. The lowest RI values, associated to aerobic stress, were found at about 200 m depth and decreased towards the Equator. Increased pCO 2 in the hypoxic water layer reduced the RI values by as much as 0.59 RI units, with the thickness of the upper water layer that presents conditions suitable for aerobic life (RI>0.7) declining by half between 42 • S and 28 • S. The intermediate waters hardly reached those stations closer to the equator so that the increased pCO 2 lowered pH and the saturation of aragonite. A significant fraction of the water column along the Chilean sector of the Humboldt Current System suffers from CO 2 -driven compromises to biota, including waters corrosive to calcifying organisms, stress to aerobic organisms or both. The habitat free of CO 2 -driven stresses was restricted to the upper mixed layer and to small water parcels at about 1000 m depth. Overall pCO 2 acts as a hinge connecting respiratory and calcification challenges expected to increase in the future, resulting in a spread of the challenges to aerobic organisms.

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Branchial chemoreceptors mediate ventilatory responses to hypercapnic acidosis in channel catfish

Cited by 66 publications

References 33 publications

Cardiac responses to hypercapnia in larval zebrafish (Danio rerio): The links between CO2 chemoreception, catecholamines and carbonic anhydrase

Cardiac responses to hypercapnia in larval zebrafish (Danio rerio): The links between CO2 chemoreception, catecholamines and carbonic anhydrase

Biological Impact of Elevated Ocean CO2 Concentrations: Lessons from Animal Physiology and Earth History

Coupled CO<sub>2</sub> and O<sub>2</sub>-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System

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Branchial chemoreceptors mediate ventilatory responses to hypercapnic acidosis in channel catfish

Cited by 66 publications

References 33 publications

Cardiac responses to hypercapnia in larval zebrafish (Danio rerio): The links between CO2 chemoreception, catecholamines and carbonic anhydrase

Cardiac responses to hypercapnia in larval zebrafish (Danio rerio): The links between CO2 chemoreception, catecholamines and carbonic anhydrase

Biological Impact of Elevated Ocean CO2 Concentrations: Lessons from Animal Physiology and Earth History

Coupled CO&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt;-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System

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Coupled CO<sub>2</sub> and O<sub>2</sub>-driven compromises to marine life in summer along the Chilean sector of the Humboldt Current System