Local power for synapses

New results from Patrik Verstreken, Hugo Bellen, and colleagues (Baylor College of Medicine, Houston, TX) show that mitochondria in axon terminals provide energy to overwrought synapses.Being far from the cell body, synapses have their own reserve of cellular machinery, including ER and mitochondria. Bellen's group analyzed the contribution of local mitochondria to synaptic function using a fly dynamin-like mutant called drp1, which lacks mitochondria at the synapse but retains them in the cell body.

Although synaptic endo- and exocytosis are thought to depend on local ATP, neurotransmission in response to slow stimulation was fairly normal in drp1 synapses. But under high frequency stimulation—such as occurs during muscle contractions—synapses at drp1 neuromuscular junctions (NMJs) ran out of steam.

The failure stemmed from an inability of...