Prolonged activation of mitochondrial conductances during synaptic transmission.
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 ( approximately 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.
Jonas
E A
EA
Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.
Buchanan
J
J
Kaczmarek
L K
LK
D000200:Action Potentials; D000818:Animals; D002118:Calcium / Q000378:metabolism; D015220:Calcium Channels / Q000378:metabolism; D049832:Decapodiformes; D004553:Electric Conductivity; D004558:Electric Stimulation; D007425:Intracellular Membranes / Q000378:metabolism; D007473:Ion Channels / Q000378:metabolism*; D017136:Ion Transport; D008854:Microscopy, Electron; D008928:Mitochondria / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D018272:Porins / Q000378:metabolism; D017729:Presynaptic Terminals / Q000378:metabolism* / Q000648:ultrastructure; D009435:Synaptic Transmission; D013997:Time Factors; D050994:Voltage-Dependent Anion Channels
D015220:Calcium Channels; D007473:Ion Channels; D018272:Porins; D050994:Voltage-Dependent Anion Channels; D002118:Calcium