EPSP question

[ber55ber55]

Provide three examples of how different

neurotransmitter receptors can combine to generate different EPSPs.

 

Where would i find this, and also an example with an experiment of some sort would be nice.. Thanks in advance

[iNow]

Provide three examples of how different

neurotransmitter receptors can combine to generate different EPSPs.

 

Where would i find this, and also an example with an experiment of some sort would be nice.. Thanks in advance

 

Where are you stuck? Can you share what you know already? If you do, it might be easier to point you in the right direction.

 

 

For others, here is a definition of Excitatory Post-Synaptic Potentials (EPSPs):

 

http://www.biochem.northwestern.edu/holmgren/Glossary/Definitions/Def-E/EPSP.html

An electrical change (depolarisation) in the membrane of a postsynaptic neurone caused by the binding of an excitatory neurotransmitter from a presynaptic cell to a postsynaptic receptor; makes it more likely for a postsynaptic neurone to generate an action potential.

 

 

... and a link to the wiki article on same:

 

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

[ber55ber55]

Well I understand how EPSP's work and I know the different neurotransmitters are such as acetylcholine, but I dont understand what combos I can make. Thanks

[iNow]

Hmmm... Honestly, I don't know the answer to your question:

 

Provide three examples of how different neurotransmitter receptors can combine to generate different EPSPs.

 

I suppose there are more than three possible answers though, so be creative.

 

 

One part to recall is that there are two different types of post-synaptic receptors:

Ionotropic Receptors (Ligand-gated Ion channels)

Metabotropic Receptors (G-protein linked receptors).

 

Maybe you can start there?

 

http://www.williams.edu/imput/III.html

After release into the synaptic cleft, neurotransmitters interact with receptor proteins on the membrane of the postsynaptic cell, causing ionic channels on the membrane to either open or close. When these channels open, depolarization occurs, res ulting in the initiation of another action potential.

 

There are two types of postsynaptic receptors that recognize neurotransmitters. Ionotropic receptors, also referred to as ligand-gated ion channels, act quickly to depol arize the neuron and pass on the action potential (or hyperpolarize the neuron and inhibit additional action potentials). These receptors are made up of five individual protein subunits embedded in the cell membrane, and arranged to form a single pore th at spans this membrane. When a neurotransmitter associates with the extracellular recognition site, the membrane-spanning subunits of the receptor quickly open to form a pore through which the necessary ions can pass. Depolarization usually occurs a m illisecond or two after the action potential has been received and lasts only up to ten milliseconds.

 

?-aminobutyric acid(GABA) is one example of a neurotransmitter recognized by an ionotropic receptor. GABA is an inhibitory neurotransmitter used at roughly one-third of the synapses in the brain. The binding of GABA at the GABA recognition site c auses the membrane-spanning channel of the receptor protein to open and allow an influx of negatively charged chloride ions. This influx of negative ions serves to hyperpolarize the cell thus inhibiting the firing of an action potential. Though in the c ase of GABA, the ionotropic receptor is used to inhibit the firing of an action potential, there are other ionotropic receptors which recognize excitatory neurotransmitters and thus stimulate the firing of action potentials in post-synaptic cells. < /P>

 

Metabotropic receptors, or G-protein linked receptors, do not work as simply as ligand-gated ion channels do. Like ionotropic receptors, metabotropic receptors also have an extracellular neurotransmitter recognition site, yet these receptors do not form a membrane-spanning pore that can allow the direct passage of ions. Instead, when a neurotransmitter associates with the extracellular recognition site, an intermediate molecule within the postsynaptic cell, called a G-protein, is activated and, either directly or through a series of enzymatic reactions, opens or closes ion channels located at other places on the cell membrane. Because the action of metabotropic recepto rs is not as direct, their action is slower. Depolarization takes longer, typically lasting up to hundreds of milliseconds, and in some cases, going on for several minutes, hours, or even days.

 

Metabotropic receptors are used in the recognition of all neuropeptides and several small-molecule neurotransmitters. Dopamine (DA), for example, is a small-molecule neurotransmitter recognized by a G-protein coupled receptor. The binding of DA a t the recognition site of a post-synaptic DA receptor sets off a chain of reactions which ultimately cause ion pores along the post-synaptic membrane to open and an action potential to be stimulated. Found in four major tracts of the brain (the nigrostri al tract, the tuberoinfundibular tract, the mesolimbic tract, and the mesocortical tract), DA plays an important role in the control of both motor and emotional behavior.

[ber55ber55]

thank you for your help. I think its talking about how pre can reg pre, etc. For example a GABA can reg GABA instead of Glu and the AP and EPSP will be higher for the Glu1 insteadof having the gaba reg on the Glu. Im gonna try that and see if its right.Thanks again iNow