Cold acclimation increases depolarization resistance and tolerance in muscle fibers from a chill-susceptible insect, Locusta migratoria

0534513 - BC 2021 RIV US eng J - Journal Article
Bayley, M. - Sorensen, J. G. - Moos, Martin - Košťál, Vladimír - Overgaard, J.
Cold acclimation increases depolarization resistance and tolerance in muscle fibers from a chill-susceptible insect, Locusta migratoria.
American Journal of Physiology-Regulatory Integrative and Comparative Physiology. Roč. 319, č. 4 (2020), R439-R447. ISSN 0363-6119. E-ISSN 1522-1490
Institutional support: RVO:60077344
Keywords : acclimation * cold exposure * depolarization
OECD category: Biology (theoretical, mathematical, thermal, cryobiology, biological rhythm), Evolutionary biology
Impact factor: 3.619, year: 2020
Method of publishing: Limited access
https://journals.physiology.org/doi/abs/10.1152/ajpregu.00068.2020

Cold exposure depolarizes cells in insects due to a reduced electrogenic ion transport and a gradual increase in extracellular K+ concentration ([K+]). Cold-induced depolarization is linked to cold injury in chill-susceptible insects, and the locust, Locusta migratoria, has been shown to improve cold tolerance following cold acclimation through depolarization resistance. Here we investigate how cold acclimation influences depolarization resistance and how this resistance relates to improved cold tolerance. To address this question, we investigated if cold acclimation affects the electrogenic transport capacity and/or the relative K+ permeability during cold exposure by measuring membrane potentials of warm- and cold-acclimated locusts in the presence and absence of ouabain (Na+-K+ pump blocker) or 4-aminopyridine (4-AP: voltage-gated K+ channel blocker). In addition, we compared the membrane lipid composition of muscle tissue from warm- and cold-acclimated locust and the abundance of a range transcripts related to ion transport and cell injury accumulation. We found that cold-acclimated locusts are depolarization resistant due to an elevated K+ permeability, facilitated by opening of 4-AP-sensitive K+ channels. In accordance, cold acclimation was associated with an increased abundance of Shaker transcripts (gene encoding 4-AP-sensitive voltage-gated K+ channels). Furthermore, we found that cold acclimation improved muscle cell viability following exposure to cold and hyperkalemia even when muscles were depolarized substantially. Thus cold acclimation confers resistance to depolarization by altering the relative ion permeability, but cold-acclimated locusts are also more tolerant to depolarization.
Permanent Link: http://hdl.handle.net/11104/0315258