Question | Answer |
gap junctions | site of (rarer) electrical synapses. spanned by special proteins called 'connexins', six of which form a channel which allow ions to pass directly. bi. usually found in invertebrates btwn sense and motor neurons [thus "electrotonically coupled"] bc fast |
gray's type 1 synapse | synapse wherein the membrane on the post-synaptic side is thicker than presynaptic; excitatory |
gray's type 2 synapse | synapse wherein membrane is similar thickness at post and pre synapse; usually inhibitory b/c there are more gates down closer to the soma to open and let Cl in and inhibit. |
secretory granules | larger vesicles [than synaptic vesicles] located in the axon terminal, containing soluble protein (neurotransmitter: peptides). AKA large dense-core vesicles. |
active zones | proteins that jut into the terminal from the presynaptic side. site of neurotransmitter release. they differentiate pre and post (or not, in inhibitory) |
postsynaptic density | protein accumulated in and under the postsynaptic membrane. these are the receptors for neurotransmitters |
amino acid transmitters | examples: gamma-amino butyric acid (GABA), glutamate (Glu), Glycine (Gly)
(small, organic, contain nitrogen) |
amines (neurotransmitters) | ex: acetylcholine (ACh), dopamine (DA), epinephrine, histamine, noorepinephrine (NE), serotonin (5-HT)
(small, organic, contain nitrogen) |
neuromuscular junction | what it sounds like. also: reliable, w/big synapses. post-synaptic membrane is called the motor end-plate. neurotransmitter: acetylcholine |
peptides | stored in and released from the secretory granules. larger molecules. made in the rough ER, and sorted/cleaved by the golgi apparatus, where they are put in their secretory granules. takes more than one AP to release them. |
glutamate | one of the 20 amino acid "building blocks" (so abundant) |
glycine | one of the 20 amino acid "building blocks" (so abundant) |
GABA | only made by the neurons that release it |
transporters | special proteins embedded in the membrane of the synaptic vesicles, whose job it is to get the neurotransmitters into the vesicles |
exocytosis | as Ca2+ floods into the presynaptic terminal (since the depolarization opened up the calcium gates), this is the process by which the calcium causes the vesicles to fuse w/the membrane and release their contents. unfortunately, actual mechanism is unknown |
endocytosis | process by which vesicle is recovered after exocytosis |
transmitter-gated ion channels | unlike voltage gated ion channels, these channels, opening upon reception of a neurotransmitter, are less selective. neverthless the net effect will be depolarization, and therefore excitatory |
g-protein-coupled receptors | AKA metabotropic receptors. upon neurotransmitter arrival, these receptors activate G-proteins, which activate "effector" proteins |
effector proteins | can be a) G-protein gated ion channels, or b)enzymes that generate molecules called secondary messengers, which can activate additional enzymes in the cystol that can regulate ion channel fxn and alter cell metabolism |
IPSP | inhibitory post-synaptic potential. Cl- floods in, forcing the cystol to tend towards a negative voltage. glycine-gated and GABA-gated ion channels both do this |
autoreceptors | receptors at the presynapse which are sensitive to the transmitters that that presynapse releases. often are g-protein-coupled receptors which work on secondary messengers to inhibit. (overflow safety drain dealio?) |
acetylcholinesterase | an example of neurotrasmitter removal, AChE is used after a neuromuscular presynaptic firing releases ACh. If ACh stayed there, the post-synapse would become desensitized to its presence, and further APs would do nothing. AChE binds to ACh, removing it |
miniature postsynaptic potential | aka mini. low rate of continual nt release causes low base postsynaptic response. since its one vesicles, its the quanta |
integration of EPSPs | CNS neurons fire very weak synapses, and numerous EPSPs on the dendrites ("spatial summation") or multiple APs must combine succesively within 1-15msec ("temporal summation") to make the postsynapse depolarize |
dendritic length constant | the distance at which the depolarization of the dendrite is 37% of that of the base (rand number? no, based on e) |
internal resistance | inverse of conductance of a neuron's dendrite, depending on thickness and electrical properties of cytoplasm. stays fairly constant for any given neuron |
membrane resistance | resistance of a neuron's dendrite's membrane, depending on the number of open ion channels, which is very variable. (number of holes in leaky hose) |
shunting inhibition | inhibition where, b/c so much chloride is coming in, voltage stays around -65mv and APs don't happen |
modulation | synptc trans where EPSPs are not created but modified in effctvnss. effect (eg, chnging K+ conc and thus incr conduct) can last longer than cause (conversion of ATP into cAMP, stimulation by cAMP of protein kinases, phosphorylation by protein kinases) |