title: Activity dependence of spreading depression in the locust CNS.
abstract: Spreading depression (SD) is associated with large changes in extracellular ion concentrations and can be induced by impairing mechanisms of K(+) ion homeostasis. We tested activity dependence of SD in the locust model of ouabain-induced SD in the metathoracic ganglion. Wind activation of thoracic circuitry resulted in small increases of K(+) concentration that took 5-10 s to be cleared from the extracellular space. In the presence of the Na(+)/K(+)-ATPase inhibitor ouabain, wind stimulation every 30 s halved the latency to the first SD event and increased its duration. Wind stimulation was able to trigger the first event, suggesting that local activity could determine the origin of successive SD events. Perfusion with calcium-free saline blocked neural activity in the ganglion and prevented the occurrence of ouabain-induced SD. We conclude that ouabain-induced SD in the locust CNS is strongly dependent on the existing level of neural activity.
authors.affiliation: Department of Biology, Queen's University, Bioscience complex, Room 3404, Kingston, Ontario, Canada K7L 3N6 9ks26@queensu.ca.
authors.forename: Kristin E
authors.initials: KE
authors.lastname: Spong
authors.affiliation: Department of Biology, Queen's University, Bioscience complex, Room 3404, Kingston, Ontario, Canada K7L 3N6.
authors.forename: Tom R
authors.initials: TR
authors.lastname: Mazzetti
authors.affiliation: Department of Biology, Queen's University, Bioscience complex, Room 3404, Kingston, Ontario, Canada K7L 3N6.
authors.forename: R Meldrum
authors.initials: RM
authors.lastname: Robertson
mesh_terms: D000818:Animals; D002490:Central Nervous System / Q000187:drug effects / Q000502:physiology; D005110:Extracellular Space / Q000378:metabolism; D006706:Homeostasis; D048188:Locusta migratoria / Q000502:physiology*; D008297:Male; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism; D014919:Wind
chemical_list: D010042:Ouabain; D011188:Potassium
keywords: Locusta migratoria; Metathoracic ganglion; Ouabain; Potassium