# Tackling neurotransmission precision

**URL:** <http://discourse.iapct.org/t/tackling-neurotransmission-precision/11006>\
**Category:** CSG2014\
**Created:** [December 22, 2014, 5:19pm UTC](http://discourse.iapct.org/t/tackling-neurotransmission-precision/11006 "2014-12-22T17:19:45Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![tedcloak](http://discourse.iapct.org/letter_avatar_proxy/v4/letter/t/ba8739/32.png) [@tedcloak](http://discourse.iapct.org/u/tedcloak)\
**Post date:** [December 22, 2014, 5:19pm UTC](http://discourse.iapct.org/t/tackling-neurotransmission-precision/11006/1 "2014-12-22T17:19:45Z")

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From Human Ethology listserv. This is an excellent example of proper reductionism, IMO.

To see the pictures, click the URL at the bottom of the message.

Ted

> **···**
>
> ## 1
> 
> ## [ Tackling
> 
> neurotransmission precision ]([https://groups.yahoo.com/neo/groups/human-ethology/conversations/topics/63849;\_ylc=X3oDMTJzMWpzYmoxBF9TAzk3MzU5NzE1BGdycElkAzE5NDU5MzAzBGdycHNwSWQDMTcwNTA4MzEyNQRtc2dJZAM2Mzg0OQRzZWMDZG1zZwRzbGsDdm1zZwRzdGltZQMxNDE5MjQ5MDAy](https://groups.yahoo.com/neo/groups/human-ethology/conversations/topics/63849;_ylc=X3oDMTJzMWpzYmoxBF9TAzk3MzU5NzE1BGdycElkAzE5NDU5MzAzBGdycHNwSWQDMTcwNTA4MzEyNQRtc2dJZAM2Mzg0OQRzZWMDZG1zZwRzbGsDdm1zZwRzdGltZQMxNDE5MjQ5MDAy))
> 
> #### Sun Dec 21, 2014 6:49 am (PST) . Posted by:
> 
> ### “Jay Feierman”
> 
> jrfeier
> 
> _Tackling neurotransmission precision_  
> December 18th, 2014 in Neuroscience
> 
> Freeze fracture replica image showing the voltage-gated calcium channels  
> clusters on presynaptic membrane in rats. The green circles represent  
> channel clusters, and inside each green circle are small black dots, which  
> are the individual channels. This is easier to see in the inset, labeled  
> A3, where the channels are blue dots. Credit: Professor Tomoyuki Takahashi
> 
> Behind all motor, sensory and memory functions, calcium ions are in the  
> brain, making those functions possible. Yet neuroscientists do not entirely  
> understand how fast calcium ions reach their targets inside neurons, and  
> how that timing changes neural signaling. Researchers at the Okinawa  
> Institute of Science and Technology Graduate University have determined how  
> the distance from calcium channels to calcium sensors on vesicles affects a  
> neuron’s signaling precision and efficacy.
> 
> In international collaboration with research institutes such as the Pasteur  
> Institute and the Institute of Science and Technology Austria, Professor  
> Tomoyuki Takahashi and the Cellular and Molecular Synaptic Function Unit  
> described the locations of voltage-gated calcium channels, which allow  
> calcium ions to enter into the neuron, triggering vesicles to release  
> neurotransmitters, signaling to the next neuron. This research, to be  
> published the January 7, 2015 issue of Neuron, illuminates decades of  
> mystery behind the precision and efficacy of neurotransmitter release,  
> suggesting how signaling changes as an animal matures.
> 
> After an electrical spike, or an instantaneous change in voltage, travels  
> through the neuron, it reaches the presynaptic terminal. The presynaptic  
> terminal is an area facing the synaptic cleft, or the gap between one  
> neuron and the next. The electrical spike triggers voltage-gated calcium  
> channels to open, allowing calcium ions to enter the presynaptic terminal.  
> The calcium ions then diffuse locally around the channels and encounter  
> synaptic vesicles, small packages of neurotransmitters, which are signaling  
> molecules. The calcium ions interact with sensor proteins on the vesicle,  
> triggering the vesicles to fuse with the presynaptic terminal membrane, and  
> releasing neurotransmitters into the synaptic cleft toward the next neuron.
> 
> Yet researchers have never fully grasped how calcium travels from gated  
> channel to vesicle. Some researchers argued that the channels were spread  
> across the active zone of the presynaptic terminal, while others argued  
> that a ring of gated channels surrounded each vesicle. Therefore,  
> Takahashi’s project began with an electron microscope technique, where the  
> researchers froze the presynaptic membrane and broke it open to expose the  
> calcium channels. They found that the channels existed in clusters, with a  
> variable number of channels in each cluster.
> 
> Next, the researchers ran various tests and simulations to determine how  
> the channel clusters impact signaling. They found that clusters with more  
> calcium channels more effectively trigger a nearby vesicle to release  
> neurotransmitters. Importantly, channel clusters closer to vesicles trigger  
> neurotransmitter release more quickly and more efficiently than clusters  
> located farther from vesicles, increasing signal precision. “The calcium  
> sensor on vesicles need a high concentration of calcium to trigger vesicle  
> release,” Takahashi said. “If the calcium entered from farther away, then  
> it would diffuse into a lower concentration or bind to other proteins  
> before reaching the calcium sensor on the vesicle.”
> 
> New model that Professor Takahashi and his collaborators have proposed.  
> Circles are vesicles filled with blue neurotransmitters, and the smaller  
> grey circles are voltage-gated channels. Instead of measuring from the  
> vesicle to the center of the channel cluster (green line), Takahashi  
> suggests measuring to the perimeter of the channel cluster (red line). The  
> difference is that measuring to the center varies with the size of the  
> cluster, whereas measuring to the perimeter will always describe the  
> closest channel to the vesicle Credit: OIST  
> Takahashi and his collaborators also studied how the distance changes as  
> their rat subjects developed, and how the distance changes affect neural  
> signaling. As the rat aged from seven days to fourteen days, the distance  
> between the gated channels and the vesicle shrank from 30 nanometers to 20  
> nanometers. “This maturation is fairly significant,” Takahashi said,  
> explaining that the vesicles release much more quickly after calcium enters  
> the synapse. “The signal becomes 30% faster,” he said.
> 
> Moving forward, Takahashi and his collaborators propose the perimeter  
> release model for use in neuroscience research. This model establishes that  
> calcium channels exist in clusters and that the distance from these  
> clusters to a vesicle is significant. “If you measure the distance from the  
> center of the cluster, then this distance depends on the size of the  
> cluster,” Takahashi said. Therefore, the researchers propose the distance  
> from vesicle to gated channel clusters be measured from the perimeter of  
> the cluster, rather than the center. Distances calculated using this new  
> model can explain how signaling precision increases during development.
> 
> “If there is anything which widens this distance,” Takahashi said, “it  
> actually interferes with neural precision and it can interfere with memory  
> formation.”
> 
> Provided by Okinawa Institute of Science and Technology
> 
> “Tackling neurotransmission precision.” December 18th, 2014.  
> [http://medicalxpress.com/news/2014-12-tackling-neurotransmission-precision.html](http://medicalxpress.com/news/2014-12-tackling-neurotransmission-precision.html)
> 
> _The dinosaurs never saw that asteroid coming. What’s_\* **our** excuse?\*\*  
> ~~ Neil deGrasse Tyson\*