Prolonged Activation of Mitochondrial Conductances During Synaptic Transmission

• Published in: Science (American Association for the Advancement of Science) Vol. 286; no. 5443; pp. 1347 - 1350
• Main Authors: Jonas, Elizabeth A., Buchanan, JoAnn, Kaczmarek, Leonard K.
• Format: Journal Article
• Language: English
• Published: Washington, DC American Society for the Advancement of Science 12.11.1999; American Association for the Advancement of Science; The American Association for the Advancement of Science
• Subjects: Action Potentials; Animals; Aquatic life; Biochemistry. Physiology. Immunology; Biological and medical sciences; Calcium; Calcium - metabolism; Calcium Channels - metabolism; Cell membranes; Cell organelles; Cellular biology; Decapodiformes; Electric Conductivity; Electric Stimulation; Electrodes; Fundamental and applied biological sciences. Psychology; Intracellular Membranes - metabolism; Invertebrates; Ion channels; Ion Channels - metabolism; Ion Transport; Ions; Membranes; Microscopy, Electron; Mitochondria; Mitochondria - metabolism; Mollusca; Organelles; P branes; Patch-Clamp Techniques; Physiology. Development; Pipettes; Porins - metabolism; Presynaptic Terminals - metabolism; Presynaptic Terminals - ultrastructure; Synapses; Synaptic Transmission; Time Factors; Voltage-Dependent Anion Channels; Mitochondria; Synaptic transmission; Electrophysiology; Patch clamp method; Ionic channel; Ionic conductance; Invertebrata; Mollusca
• DOI: 10.1126/science.286.5443.1347
• ISSN: 0036-8075

Although ion channels have been detected in mitochondria, scientists have not been able to record ion transport in mitochondria of intact cells. A variation of the patch clamp technique was used to record ion channel activity from intracellular organelles in the presynaptic terminal of the squid. Electron microscopy indicated that mitochondria are numerous in this terminal and are the only organelles compatible with the tips of the pipettes. Before synaptic stimulation, channel activity was infrequent and its conductance was small, although large conductances (∼0.5 to 2.5 nanosiemens) could be detected occasionally. During a train of action potentials, the conductance of the mitochondrial membrane increased up to 60-fold. The conductance increased after a delay of several hundred milliseconds and continued to increase after stimulation had stopped. Recovery occurred over tens of seconds.