A New Nuance to Neurons

A New Nuance to Neurons link
Zhaolin Hua, Sergio Leal-Ortiz, Sarah Foss, Clarissa Waites, Craig Garner, Susan Voglmaier, Robert Edwards
August 23rd, 2011

Vesicles, the tiny neurotransmitters released from one terminal to the next neuron to send along the electrical message, has always believed to be of either two pools. In one, the recycling pool, the vesicles are sent to the next neuron to send along the message and then repackaged to be used again. In the other, the resting pool, it appears they just sit there to the side and do nothing. About 80% of all vesicles appear to be in the resting pools. Scientists could never determine or understand the reason between the two pools or what the resting pools function was for. And not only that but they couldnt tell the difference between the different kinds of vesicles other than by their location because visually they appeared the exact same. It was believed that where they happened to end up determined what pool they were in as opposed to being preassigned what their function will be and thus executes it.

In their paper, Edwards and his colleagues show that vesicles in the two different pools contain different proteins and that these differences determine how they behave. Using a technique for labeling proteins with glowing molecules derived from jellyfish, they were able to show that a protein called VAMP7 is present at high levels in the resting pool rather than the recycling pool, which contains more of other synaptic vesicle proteins.

This shows that the body makes and maintains different pools of vesicles containing different proteins for different purposes: release or some other function. According to Edwards, the observation has far-reaching implications for our understanding of how neurotransmitters are packaged, transported and released from neurons.

According to Edwards, resting vesicles are involved in a separate not-well-understood process in which neurons spontaneously release vesicles, which may help them adjust the types of connections they make with each other as well as the strength of those connections. This process may play a role in neurological diseases, many of which are characterized by changes in the type and strength of synapses.