Developmental changes in central O2 chemoreflex in <i>Rana catesbeiana</i>: the role of noradrenergic modulation

Fournier, Stéphanie; Allard, Mathieu; Roussin, Stéphanie; Kinkead, Richard

doi:10.1242/jeb.005983

Cited by 29 publications

(56 citation statements)

References 42 publications

(61 reference statements)

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“…As the system matures, GABA becomes inhibitory owing to the -ions from the intracellular milieu. During development, its progressive expression plays an important role in the switch from GABA-mediated excitation to inhibition and contributes to maturation of the neural networks regulating breathing in bullfrog tadpoles (Fournier et al, 2007;Fournier and Kinkead, 2008). The processes regulating KCC2 expression during development are not entirely understood (Ben-Ari, 2002); however, the results obtained here bring us to propose that corticosterone may play an important role in this regard.…”

Section: Mechanisms Of Action Of Corticosteronementioning

confidence: 70%

“…The cranium was opened to expose the brainstem and rostral spinal cord, and to allow dissection of the cranial nerves. The brain was irrigated with ice-cold (0-5°C) artificial cerebrospinal fluid (aCSF) to avoid a sudden change in temperature and reduce axonal conductance throughout the dissection procedure (Fournier et al, 2007). The composition of the aCSF was identical to that developed for Xenopus laevis (Zornik and Kelley, 2008) and consisted of (mmoll -1 ): NaCl 75.0, KCl 2.0, MgCl 2 0.5, D-glucose 11.0, NaHCO 3 25.0 and CaCl 2 2.0.…”

Section: In Vitro Brainstem Preparationsmentioning

confidence: 99%

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Corticosterone promotes emergence of fictive air breathing in Xenopus laevis Daudin tadpole brainstems

Fournier

Dubé

Kinkead

2012

Journal of Experimental Biology

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SUMMARY The emergence of air breathing during amphibian metamorphosis requires significant changes to the brainstem circuits that generate and regulate breathing. However, the mechanisms controlling this developmental process are unknown. Because corticosterone plays an important role in the neuroendocrine regulation of amphibian metamorphosis, we tested the hypothesis that corticosterone augments fictive air breathing frequency in Xenopus laevis. To do so, we compared the fictive air breathing frequency produced by in vitro brainstem preparations from pre-metamorphic tadpoles and adult frogs before and after 1 h application of corticosterone (100 nmol l–1). Fictive breathing measurements related to gill and lung ventilation were recorded extracellularly from cranial nerve rootlets V and X. Corticosterone application had no immediate effect on respiratory-related motor output produced by brainstems from either developmental stage. One hour after corticosterone wash out, fictive lung ventilation frequency was increased whereas gill burst frequency was decreased. This effect was stage specific as it was significant only in preparations from tadpoles. GABA application (0.001–0.5 mmol l–1) augmented fictive air breathing in tadpole preparations. However, this effect of GABA was no longer observed following corticosterone treatment. An increase in circulating corticosterone is one of the endocrine processes that orchestrate central nervous system remodelling during metamorphosis. The age-specific effects of corticosterone application indicate that this hormone can act as an important regulator of respiratory control development in Xenopus tadpoles. Concurrent changes in GABAergic neurotransmission probably contribute to this maturation process, leading to the emergence of air breathing in this species.

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Section: Mechanisms Of Action Of Corticosteronementioning

confidence: 70%

Section: In Vitro Brainstem Preparationsmentioning

confidence: 99%

Corticosterone promotes emergence of fictive air breathing in Xenopus laevis Daudin tadpole brainstems

Fournier

Dubé

Kinkead

2012

Journal of Experimental Biology

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“…The cranium was opened to expose the brainstem and rostral spinal cord and to allow dissection of the cranial nerves. During dissection, the brainstem was superfused with oxygenated artificial cerebrospinal fluid (aCSF) kept at cold temperature (0-5 • C) to avoid a sudden change in temperature and reduce axonal conductance throughout the dissection procedure (Fournier et al, 2007). The composition of the tadpole aCSF consisted of (in mM): NaCl (104); KCl (4.0); MgCl 2 (1.4); NaHCO 3 (25.0); CaCl 2 (2.4); d-glucose (10.0).…”

Section: In Vitro Brainstem Preparationsmentioning

confidence: 99%

Aldosterone, corticosterone, and thyroid hormone and their influence on respiratory control development in Lithobates catesbeianus: An in vitro study

Rousseau

Bairam

Kinkead

2016

Respiratory Physiology & Neurobiology

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“…O 2 -sensitive processes that drive ventilation located in the carotid labyrinth and the aortic arch effect ventilatory increases during hypoxia in anurans (Van Vliet and West, 1992). Additionally, a centrally driven, hypoxic ventilatory depression occurs in adult bullfrogs, presumably to dampen breathing frequency during hypoxia for energy conservation (Fournier et al, 2007;Winmill et al, 2005). Similar to resting breathing, our findings suggest that overwintering conditions would not affect 'early-spring' function of O 2 -sensitive processes meditating ventilatory responses to hypoxia.…”

Section: Sensitivity To Hypoxiamentioning

confidence: 71%

Control of lung ventilation following overwintering conditions in bullfrogs,Lithobates catesbeianus

Santin

Hartzler

2016

Journal of Experimental Biology

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Ranid frogs in northern latitudes survive winter at cold temperatures in aquatic habitats often completely covered by ice. Cold-submerged frogs survive aerobically for several months relying exclusively on cutaneous gas exchange while maintaining temperature-specific acidbase balance. Depending on the overwintering hibernaculum, frogs in northern latitudes could spend several months without access to air, the need to breathe or the chemosensory drive to use neuromuscular processes that regulate and enable pulmonary ventilation. Therefore, we performed experiments to determine whether aspects of the respiratory control system of bullfrogs, Lithobates catesbeianus, are maintained or suppressed following minimal use of air breathing in overwintering environments. Based on the necessity for control of lung ventilation in early spring, we hypothesized that critical components of the respiratory control system of bullfrogs would be functional following simulated overwintering. We found that bullfrogs recently removed from simulated overwintering environments exhibited similar resting ventilation when assessed at 24°C compared with warm-acclimated control bullfrogs. Additionally, ventilation met resting metabolic and, presumably, acid-base regulation requirements, indicating preservation of basal respiratory function despite prolonged disuse in the cold. Recently emerged bullfrogs underwent similar increases in ventilation during acute oxygen lack (aerial hypoxia) compared with warm-acclimated frogs; however, CO 2 -related hyperventilation was significantly blunted following overwintering. Overcoming challenges to gas exchange during overwintering have garnered attention in ectothermic vertebrates, but this study uncovers robust and labile aspects of the respiratory control system at a time point correlating with early spring following minimal to no use of lung breathing in coldaquatic overwintering habitats.

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Developmental changes in central O2 chemoreflex in Rana catesbeiana: the role of noradrenergic modulation

Abstract: -1 ) in both stage groups. We conclude that NA modulation contributes to the central O 2 chemoreflex in bullfrog, which acts via GABA/glycine pathways. These data suggest that maturation of GABA/glycine neurotransmission contributes to the developmental changes in this chemoreflex.

Cited by 29 publications

References 42 publications

Corticosterone promotes emergence of fictive air breathing in Xenopus laevis Daudin tadpole brainstems

Corticosterone promotes emergence of fictive air breathing in Xenopus laevis Daudin tadpole brainstems

Aldosterone, corticosterone, and thyroid hormone and their influence on respiratory control development in Lithobates catesbeianus: An in vitro study

Control of lung ventilation following overwintering conditions in bullfrogs,Lithobates catesbeianus

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