Critical Oxygen Tensions of Neuronal Anoxic Defence Mechanisms in the Western Painted Turtle
Year: 2015
Type: dissertation
Abstract: The critical oxygen tension (Pcrit) is the oxygen partial pressure at which oxidative metabolism can no longer support the energetic (ATP) needs of the cell, at which point the cell must either decrease its energetic needs, or produce ATP anaerobically. The Western Painted Turtle (Chrysemys picta) is an anoxia-tolerant vertebrate species that undergoes spike arrest to conserve ATP, by activating GABAA receptors and inhibiting action potential generation. The đcrit of spike arrest was unknown and considered to be very low but my measurement suggests a range between 25 and 35 torr. Three additional changes occurred during spike arrest: mitochondrial membrane potential depolarized, cytosolic [Ca2+] increased and the production of reactive oxygen species (ROS) decreased, all of which both activate spike arrest downstream and are indicative of decreased mitochondrial respiration. My findings thus suggest that mitochondria might act as bioenergetic oxygen sensors for spike arrest once oxygen tension reachesđPcrit.
Source: TSpace (University of Toronto)
Author: Aaron Chowdhury
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W2443359597