PT  - JOURNAL ARTICLE
AU  - Rodríguez, Esteban C.
AU  - Robertson, R. Meldrum
TI  - Protective effect of hypothermia on brain potassium homeostasis during repetitive anoxia in <em>Drosophila melanogaster</em>
AID  - 10.1242/jeb.074468
DP  - 2012 Dec 01
TA  - The Journal of Experimental Biology
PG  - 4157--4165
VI  - 215
IP  - 23
4099  - http://jeb.biologists.org/content/215/23/4157.short
4100  - http://jeb.biologists.org/content/215/23/4157.full
SO  - J. Exp. Biol.2012 Dec 01; 215
AB  - Oxygen deprivation in nervous tissue depolarizes cell membranes, increasing extracellular potassium concentration ([K+]o). Thus, [K+]o can be used to assess neural failure. The effect of temperature (17, 23 or 29°C) on the maintenance of brain [K+]o homeostasis in male Drosophila melanogaster (w1118) individuals was assessed during repeated anoxic comas induced by N2 gas. Brain [K+]o was continuously monitored using K+-sensitive microelectrodes while body temperature was changed using a thermoelectric cooler (TEC). Repetitive anoxia resulted in a loss of the ability to maintain [K+]o baseline at 6.6±0.3 mmol l−1. The total [K+]o baseline variation (Δ[K+]o) was stabilized at 17°C (−1.1±1.3 mmol l−1), mildly rose at 23°C (17.3±1.4 mmol l−1), and considerably increased at 29°C (332.7±83.0 mmol l−1). We conclude that (1) reperfusion patterns consisting of long anoxia, short normoxia and high cycle frequency increase disruption of brain [K+]o baseline maintenance, and (2) hypothermia has a protective effect on brain K+ homeostasis during repetitive anoxia. Male flies are suggested as a useful model for examining deleterious consequences of O2 reperfusion with possible application for therapeutic treatment of stroke or heart attack. ADanoxic depolarization[K+]iintracellular potassium concentration[K+]oextracellular potassium concentrationΔ[K+]ototal [K+]o baseline variationMRmetabolic ratePORpercentage of recoveryΔPORtotal percentage of recovery variationRNSreactive nitrogen speciesROSreactive oxygen speciesSDspreading depressionTECthermoelectric coolertrecoverytime to recoverytsurgetime to surge