How is neurotransmitter released from a receptor?

[scilearner]

After a neurotransmitter molecule has been recognized by a post-synaptic receptor, it is released back into the synaptic cleft.

 

What makes it release back into the synpatic cleft? Also in other scenarios I have seen some ligand or something attaches to a receptor and then get released without any mention why it happened? If anyone can help. It would be great. Thanks

[ercdndrs]

You could easily find that on Wikipedia or another site.. no reason to waste other people's time

[Genecks]

What makes it release back into the synpatic cleft? Also in other scenarios I have seen some ligand or something attaches to a receptor and then get released without any mention why it happened? If anyone can help. It would be great. Thanks

 

http://en.wikipedia.org/wiki/Reuptake

 

You could easily find that on Wikipedia or another site.. no reason to waste other people's time

 

http://www.youtube.com/watch?v=_JSGczqVLLg

[iNow]

Also, be sure to look-up sodium/potassium channels.

 

Finally, I've always like the neuroscience for kids site. Really well done, easy to understand. Here's the relevant page:

http://faculty.washington.edu/chudler/chnt1.html

[scilearner]

Thank you everyone who helped but problem is not with the reuptake process. It is not that difficult to understand it once the neurotransmitter is released into the synaptic cleft but nothing mentions how it get released there. For example from iNow link

 

inactivation of Neurotransmitters

 

The action of neurotransmitters can be stopped by four different mechanisms:

1. Diffusion: the neurotransmitter drifts away, out of the synaptic cleft where it can no longer act on a receptor.

 

Now what makes the neurotransmitter break its bond with the receptor and diffuse away. Reuptake by a transport proteins is not what I after. Just how the neurotransmitter goes back to the synaptic cleft. Thanks and sorry for not making myself clear before

[Genecks]

No, that's alright.

I didn't correctly read your question the first time around.

 

Termination

 

After a neurotransmitter molecule binds to a receptor molecule, it does not stay bound forever: sooner or later it is shaken loose by random temperature-related jiggling. Once the neurotransmitter breaks loose, it can either drift away, or bind again to another receptor molecule. The pool of neurotransmitter molecules undergoing this binding-loosening cycle steadily diminishes, however. Neurotransmitter molecules are typically removed in one of two ways, depending on the type of synapse: either they are taken up by the presynaptic cell (and then processed for re-release during a later action potential), or else they are broken down by special enzymes. The time course of these "clearing" processes varies greatly for different types of synapses, ranging from a few tenths of a millisecond for the fastest, to several seconds for the slowest.

http://en.wikipedia.org/wiki/Chemical_synapse#Termination

 

My alternative guess is that either some process in the synaptic cleft or a process in the post-synaptic neuron causes an allosteric change in the receptor, thus causing the ligand to release.

 

The below is saying that rapid action potentials in the post-synaptic cell can cause the ligand to release.

 

http://www.google.com/url?sa=t&source=web&ct=res&cd=1&ved=0CAYQFjAA&url=http%3A%2F%2Fwww.slideshare.net%2Falxndr01%2Fchapter-03-synaptic-communications-presentation&rct=j&q=%22neurotransmitter+release%22+%22release+from+the+receptor%22&ei=zam9S-nxB4TWM9vvhIQK&usg=AFQjCNF7CiXVyQ5ShG9ZF8672x2VU_xtbw

 

I'm not sure of the answer.

 

Here is something more: http://userwww.service.emory.edu/~wfanteg/6.pdf

 

Look at pages 10 through 12.

Edited April 8, 2010 by Genecks

[scilearner]

No, that's alright.

I didn't correctly read your question the first time around.

 

Termination

 

 

http://en.wikipedia.org/wiki/Chemical_synapse#Termination

 

Thanks Genecks that was exactly what I was after However that raises few questions

 

"random temperature-related jiggling"

So does this mean some neurotransmitters stay connected with the receptor. How does it release the neurotransmitter at the right time if this is a random process? Can you give an example of temperature jiggling. Thanks a lot for the answer though

[Genecks]

I updated my post.

I'm not sure what the wikipedian(s) thought of "temperature jiggling."

[CharonY]

In the simplest and most common case, receptor binding is an equlibrium reaction. In other words, molecules bind to the receptor and get released constantly. This reaction is not timed. I.e. at any given time point there is a certain equilibrium of free and bound transmitters.

The rate is determined by the affinity of the molecule to the receptor. How much is bound at any given time in a population of receptors is determined by the concentration of the molecules and the amount of receptors present (also see law of mass action).

Temperature jiggling is a strange way to describe Brownian motion.

[iNow]

Well, temperature itself is just a measure of the amount and intensity of molecular level jiggling, so there's always that...