Sara J. Abdallah

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The current study investigated the role of hydrogen sulphide (H2S) in oxygen sensing, intracellular signalling and promotion of ventilatory responses to hypoxia in adult and larval zebrafish (Danio rerio). Both larval and adult zebrafish exhibited a dose-dependent increase in ventilation to sodium sulphide (Na2S), an H2S donor. In vertebrates, cystathionine(More)
Neuroepithelial cells (NECs) of the fish gill are respiratory chemoreceptors that detect changes in O2 and CO2/H+ and are homologous to type I cells of the mammalian carotid body. In zebrafish (Danio rerio), stimulation of NECs by hypoxia or hypercapnia initiates inhibition of K+ channels and subsequent membrane depolarisation. The goal of the present study(More)
Fish possess chemoreceptors able to sense increasing levels of ambient CO(2) and initiate various cardiorespiratory reflexes including hyperventilation and bradycardia. These chemoreceptors are localized predominantly to the gills, are oriented to sense the external environment and typically are stimulated by changes in environmental molecular CO(2) rather(More)
Adult zebrafish, Danio rerio, exhibit hyperventilatory responses to absolute environmental CO2 levels as low as 1.0 mmHg. The ability of zebrafish to detect and respond to low ambient CO2 appears to be mediated by chemosensory neuroepithelial cells (NECs) of the gill filaments. Recent electrophysiological characterization of this response revealed that the(More)
Nitric oxide (NO) is a gaseous neurotransmitter, which, in adult mammals, modulates the acute hypoxic ventilatory response; its role in the control of breathing in fish during development is unknown. We addressed the interactive effects of developmental age and NO in the control of piscine breathing by measuring the ventilatory response of zebrafish (Danio(More)
Severe hypoxia elicits aquatic surface respiration (ASR) behaviour in many species of fish, where ventilation of the gills at the air-water interface improves O2 uptake and survival. ASR is an important adaptation that may have given rise to air breathing in vertebrates. The neural substrate of this behaviour, however, is not defined. We characterized ASR(More)
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