Unit 2 Flashcards
What does the positive membrane potential (Nav, Kv) cause to open…
open voltage gated calcium channels
(densely located at terminal)
Calcium binds with proteins on the surface of the vesicle and activates them. What does this do?
the proteins allow vesicles to fuse with cell membrane (of PREsynaptic neuron) and release their contents (NT) into synapse
In order to release neurotransmitters, we need what to enter the cell?
CALCIUM
Do neurotransmitter pass through channels?
NOOOOOO
-bind to receptors that are connected to channels that then open allowing flow of ions
3 ways of removing Neurotransmitters
- Reuptake
- Enzymatic Degradation
- Diffusion
Reuptake
pre-synaptic terminal sucks it up and repackages it for reuse
enzymatic degradation
special enzymes in synapse destroy it
diffusion
-it slowly moves out of synapse
-concentration gradient (nt diffuse from area of high concentration to low concentration)
Glutamate
-amino acid
-most abundant excitatory NT
-binds to ligand gated Na+ channel (causes EPSP)
GABA
-amino acid
-most abundant inhibitory NT
-binds to ligand gated Cl- channel (causes IPSP)
Monomines
-indolamines
seratonin
Catecholamines
-dopamine
-norepinephrine
-epinephrine
Acetylcholine
-released at the neuromuscular junction from motorneuron
-neurons that release this are called CHOLINERGIC NEURONS
Affinity
the strength and likelihood of NT binding with receptor
-high affinity=higher binding likelihood and strength
ex. dopamine receptors have a high affinity for dopamine
Receptors come in two forms:
Iontropic receptors
Metabotropic receptors
Iontropic receptors
ligand gated channel
-when NT binds to a channel the channel opens
Iontropic receptors
-Glutamate receptors
1st AMPA- when glutamate binds with the AMPA receptor it causes the opening of Na+ channels
2nd NMDA- Has magnesium ion blocking the flux of ions through channel
-an action potential will depolarize the membrane and cause the removal of magnesium
-now when glutamate binds to receptor AGAIN, calcium can flow through channel into cell
Activation of both AMPA NMDA coupled channel will…
Increase the length of an EPSP ALOT
Iontropic receptors
-GABA receptors
-bound to inotropic Cl- channel
-causes IPSP on postsynaptic cell
ex. alcohol and Xanax (allosteric modulators of the receptor)
Metabotropic receptors
DO NOT have channel
-when a NT binds a 2nd protein is related into cell (G PROTEIN)
-effects are much slower than ionotropic
GPCRs to know
Gq
Gs
Gi
Gq
=excitatory
-increase levels of IP3 causing release of calcium
Gs
=excitatory
-increase levels of CAMP
-activates adenylyl
Gi
=inhibitory
-decreases levels of cAMP
-inhibits adenylyl