Disruption of the blood-brain barrier exacerbates spreading depression in the locust CNS.
In response to cellular stress in the nervous system of the locust (Locusta migratoria) neural function is interrupted in association with ionic disturbances propagating throughout nervous tissue (Spreading depression; SD). The insect blood-brain barrier (BBB) plays a critical role in the regulation of ion levels within the CNS. We investigated how a disruption in barrier function by transient exposure to 3M urea affects locusts' vulnerability to disturbances in ion levels. Repetitive SD was induced by bath application of ouabain and the extracellular potassium concentration ([K(+)]o) within the metathoracic ganglion (MTG) was monitored. Urea treatment increased the susceptibility to ouabain and caused a progressive impairment in the ability to maintain baseline [K(+)]o levels during episodes of repetitive SD. Additionally, using a within animal protocol we demonstrate that waves of SD, induced by high K(+), propagate throughout the MTG faster following disruption of the BBB. Lastly, we show that targeting the BBB of intact animals reduces their ability to sustain neural function during anoxic conditions. Our findings indicate that locust's ability to withstand stress is diminished following a reduction in barrier function likely due to an impairment of the ability of neural tissue to maintain ionic gradients.
Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada. Electronic address: 9ks26@queensu.ca.
Kristin E
KE
Spong
Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Geneviève
G
Rochon-Terry
Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
Tomas G A
TG
Money
Department of Biology, Queen's University, Kingston, Ontario K7L 3N6, Canada.
R Meldrum
RM
Robertson
D000818:Animals; D001812:Blood-Brain Barrier / Q000187:drug effects; D002490:Central Nervous System / Q000503:physiopathology; D005071:Evoked Potentials / Q000187:drug effects*; D006706:Homeostasis / Q000187:drug effects; D007477:Ions / Q000378:metabolism; D048188:Locusta migratoria / Q000502:physiology*; D008297:Male; D010042:Ouabain / Q000494:pharmacology*; D011188:Potassium / Q000378:metabolism; D013312:Stress, Physiological / Q000187:drug effects; D014508:Urea / Q000494:pharmacology*
D007477:Ions; D010042:Ouabain; D014508:Urea; D011188:Potassium
Blood–brain barrier; Glia; Ionic homeostasis; Locust; Potassium; Spreading depression