10.18 Synapses and Synaptic Transmission Flashcards
chemical synapses are __________ while electrical synapses are __________ (directionality)
unidirectional
bidirectional
what is the starting material to make acetylcholine?
choline (diet) + Acetyl CoA
what is the enzyme that synthesizes acetylcholine from choline and acetyl CoA
choline acetyltransferase
what is the essential amino acid that dopamine comes from?
tyrosine
what is the essential amino acid that norepinephrine comes from?
tyrosine
what is the rate limiting enzyme of the synthesis of norpei?
tyrosine hydroxylase
what is the rate limiting enzyme of the synthesis of dopamine?
tyrosine hydroxylase
norepinephrine is made from what other NT? what enzyme is needed to do this?
dopamine
dopamine beta-hydroxylase
outline the pathway to make dopamine
tyrosine –> tyrosine hydroxylase –> DOPA –> DOPA decarboxylase –> dopamine
what does dopamine beta-hydroxylase do?
converts dopamine to norepinephrine
what common amino acid is serotonin synthesized from?
what rate limiting enzyme does this?
tryptophan
tryptophan hydroxylase
outline the path in the making of serotonin
tryptophan –> tryptophan hydroxylase –> intermediate –> a decarboxylase –> serotonin
what is GABA synthesized from?
with what rate limiting enzyme?
glutamate
glutamic acid decarboxylase
what is the rate limiting step for the synthesis of GABA from __________.
glutamate
glutamic acid decarboxylase
the influx of what ion in the pre-synaptic cleft allows for release of NT?
calcium
what are the two types of receptors that could be found on the post-synaptic cell membrane?
NT-gated channels - ions
2nd messenger gated channels
what ions would cause an EPSP?
Na+ and Ca++
influx
are EPSPs and IPSPs electrotonic or an action potential?
electrotonic
what ions (and which direction of flow) would cause an IPSP?
the efflux of K+
the influx of Cl-
process by which successive synaptic potentials at the same site are added together
temporal summation
integration of input of many inputs from different sites at the same time
spatial summation
what are the three ways NT may be removed from the synaptic cleft?
diffusion
reuptake
enzymatic catabolism
how is acetylcholine generally terminated in the synaptic cleft?
enzymatic degradation by
acetylcholinesterase
what is the mechanism by which local anesthetics decrease pain?
blocking VG Na+ channels
what are some side effects of local anesthetics?
high doses can result in death
blockade of respiration
cardiovascular problems
depress smooth muscle contraction
high doses that cross bbb can also cause seizures
what are the two mechanisms in which NMJ blockers can work?
- competitive inhibition od Ach at the nicotinic channels (nicotinic receptor antagonists)
- depolarization blockade (succinylcholine)
succinylcholine is an _______ at the nicotinic receptor, causing what?
agonist
muscle contraction
where are there electrical synapses?
some dendrites
Schwann and glial cells
cardiac muscle
what connection do electrical synapses have with the demyelination in Charcot-Marie-Tooth?
improper connexion 32 protein - membranes in Schwann cells can’t communicate - Schwann cells die
demyelination
what are the biogenic amine NTs?
dopamine, norepi, serotonin
what are the amino acid NTs?
glutamate, aspartate, GABA, glycine
what allows for an acidic internal environment of vesicles? what is it used for?
vacuolar proton pump
uses the proton gradient to pump NT back into vesicle
what does monoamine oxidase (MAO) do?
breaks down dopamine and NE, and serotonin
all local anesthetics end in ________
caine
lidocaine
class type mechanism
local anesthetic
amide
blocks VG Na+ channel
medium acting
prilocaine
class type mechanism
local anesthetic
amide
blocks VG Na+ channel
medium acting
mepivacaine
class type mechanism
local anesthetic
amide
blocks VG Na+ channel
medium acting
ropivacaine
class type mechanism
local anesthetic
amide
blocks VG Na+ channels
long acting
bupivicaine
class type mechanism
local anesthetic
amide
blocks VG Na+
long acting
etidocaine
class type mech
local anesthetic
amide
blocks VG Na+ channels
long acting
