Test 2: lecture 20-21 Flashcards
what are the most common neurotransmitters
glutamate, gaba, glycine
gluatamte is the major — neurotransmitter
excitatory (allows + into the cell → depolarization)
what are the three major classes of ionotropic glutamate receptors
NMDA
Kainate
AMPA
all ionotropic glutamate receptors are — channels
cation (allow + through, let K out and Na into the cell)
are excitatory- will cause depolarization of the cell
ketamine will block
NMDA ionotropic glutamate receptor
will stop depolarization (calm it down)
too much glutamate will do what to neurons
cause cell death!
how can glutamate lead to neurotoxicity and cell death
glutamate allows Na into a cell and K out, if too active the increase in Na will cause H20 to come into cell and cause swelling → cell lysis
can also cause delayed apoptosis
how is glutamate removed from the synapse
reuptake by ecitatory amion acid transporters (EAATS)
glial cells will also reuptake glutamate, turns it into glytamine and brings it back to presynaptic neuron for recycling
Excitatory Amino Acid Transporters (EAATs) are powered by —
electrochemical gradient (Na/K)
glutamate will cause Na into the synapse, K into the cell
will pull glutamate back into presynaptic neuron for recycling
how does ischemia effect NMDA activation
decreased blood flow= loss of Na/K pump= loss of membrane potention in the synapse
no potential means glutamate released will not reuptake by EAATs- this leads to prolonged NMDA activation → too much Na into the cell → swelling → cell death
domoic acid
toxin in marine algae
agonist for kainate receptor (type of ionotropic glutamate receptor)
leads to headache, confusion, muscle weakness and coordination deficits
the BIRDS
— is the major inhibitor neurotransmitter in CNS. and is used for inhibitory control of —
GABA
Important in inhibitory control of interneurons
GABA is made from
glutamate
glutamic acid decarboxylase (GAD)
neuron can not release both GABA and glutamate= one or the other
reuptake of GABA
same as glutamate
by GABA specific EAAT and glial cells
two types of GABA receptors
GABA A receptors are —
Cl- channels
allow Cl into the cell= inhibitory = hyperpolarization
GABA B receptors are —
G protein coupled
are connected to K+ channels (move K+ out of cell) to cause membrane hyperpolarization
inhibitory
benzos bind to what receptors and will do what?
bind to GABA A receptors
make it easier to channel to open= increases Cl- into the cell = inhibitory/ hyperpolarization of the cell
benzodiazepam (valium), alprazolam (xanax)
barbiturates bind to what receptors and will do what?
bind to GABA A receptors
channels stay open longer= increases Cl- into the cell = inhibitory/ hyperpolarization of the cell
barbiturate= phenobarbital
what are some barbiturates?
sodium amytal, pentobarbital, phenobarbital
what are barbiturates used for in vet med
sodium amytal, pentobarbital, phenobarbital
used for sedation, anesthesia, and seizure control depending on the duration of action by the drugs.
causes respiratory depression in high dose = euthanasia
barbiturates bind to GABA A receptors and make them open longer allowing more Cl- into cell → inhibitory
what are some bad symptoms of barbiturate use
can cause confusion, imparied judgment and slow reflexes
lethal at high dose→respiratory depression
high tolerance
bad withdrawal
easily and commonly abused
sodium amytal, pentobarbital, phenobarbital - used for sedation, anesthesia, and seizure control in animals
binds to GABA A receptors and make them stay open longer= inhibitory