Neural effects of elevated CO2 in fish may be amplified by a vicious cycle

Schunter, Celia, Ravasi, Timothy, Munday, Philip L., and Nilsson, Goran E. (2019) Neural effects of elevated CO2 in fish may be amplified by a vicious cycle. Conservation Physiology, 7 (1).

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Abstract

Maladaptive behavioural disturbances have been reported in some fishes and aquatic invertebrates exposed to projected future CO2 levels. These disturbances have been linked to altered ion gradients and neurotransmitter function in the brain. Still, it seems surprising that the relatively small ionic changes induced by near-future CO2 levels can have such profound neural effects. Based on recent transcriptomics data, we propose that a vicious cycle can be triggered that amplifies the initial disturbance, explaining howsmall pH regulatory adjustments in response to ocean acidification can lead to major behavioural alterations in fish and other water-breathing animals. The proposed cycle is initiated by a reversal of the function of some inhibitory GABA(A) receptors in the direction of neural excitation and then amplified by adjustments in gene expression aimed at suppressing the excitation but in reality increasing it. In addition, the increased metabolic production of CO2 by overexcited neurons will feed into the cycle by elevating intracellular bicarbonate levels that will lead to increased excitatory ion fluxes through GABA(A) receptors. We also discuss the possibility that an initiation of a vicious cycle could be one of the several factors underlying the differences in neural sensitivity to elevated CO2 displayed by fishes.

Item ID: 62908
Item Type: Article (Research - C1)
ISSN: 2051-1434
Keywords: Ocean acidification, hypercapnia, GABA, behaviour, fish, brain
Copyright Information: (C) The Author(s) 2019. Published by Oxford University Press and the Society for Experimental Biology. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Date Deposited: 22 Apr 2020 07:44
FoR Codes: 05 ENVIRONMENTAL SCIENCES > 0501 Ecological Applications > 050101 Ecological Impacts of Climate Change @ 50%
06 BIOLOGICAL SCIENCES > 0608 Zoology > 060806 Animal Physiological Ecology @ 50%
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