exam 1 study night Flashcards
acetylcholine
excitatory
in PNS at neuromuscular junctions
released by cholinergic neurons
implicated in Alzheimers
neurons release ACh
cholinergic
at neuromuscular junctions
synthesis of Ach
choline and acetyl coA in cytoplasm of synaptic terminals
- cholinergic
AChe
destroys/inhibits ACh
releases choline to resume for synthesis
nerve gas sarin
inhibits AChe
Ache inhibits ACh
inhibit Ache = buildup of ACh in synaptic cleft and overtime. receptors causes desensitization
ACh receptors
- nicotinic - ligand gated ion channel bind nicotine and ACh.
ion channel permeable to K+ and Na
- Na larger driving force = depolarization due to Na+ influx - muscarinic - cholinergic receptor stimulated by Ach and muscarine . g protein or 2nd messenger coupled
nicotinic receptors
for ACh
ligand gated ion channel binds nicotine and Ach
permeable for k and Na
Na has greater driving force and Na influx causes depolarization
cholinergic
neurons release Ach
atropine
antagonist of muscarine receptors of Ach
antagonist of muscarine Ach receptors
atropine
Alzeihmers
depleted cholinergic neuron
increase beta amyloid proteins cause cell deth
biogenic amines
catecholamines and serotonin
small charged synthesized from Rs
DA, NE, Epi, Sero, Hist.
catecholamines
DA, NE, Epi (Y) –> L-dopa by rate limiting enz
epinephrine is NOT common NT in CNS but is major hormone of adrenals
Epi
major hormone from adrenals. not common NT
catecholamine
MAO
breaks down catecholamines
MAO inhibitors
drugs increase NE and DA in synapse by slowing down degradation
receptors for Epi and NE
METABOTROPIC 1. alpha androgenic:
a1 - act on postsynaptic nerve to change activity go K+ channels
a2 = act presynaptic to inhibit NE release
2. beta-androgenic
1,2,3 - stimulatory G proteins messenger increase cAMP in postsynaptic cell
CATECHOLAMINE RECEPTOR
metabotropic
serotonin
prod from W essential
slow onset
excitatory effect on muscles
inhibitory on sensations
NO activity during sleep
5-HT monoamine hormone
SRRI
inactivate presynaptic transport which mediates serotonin reuptake in presynaptic cell which increases the conc. of NT
By blocking its reuptake, SSRIs increase the concentration of serotonin in the synaptic cleft, enhancing neurotransmission
AA NT
glutamate and GABA, glycine
glutamate
AA NT
EXCITATORY
50% excitatory synapses in CNS
majority inotropic receptors
glutamate receptors
mostly inotropic in postsynaptic membranes
- AMPA, excitatory
- NMDA
channels
AMPA and NMDA receptors
channels
show cooperatively
receptors for glutamate excitatory in postsynaptic membranes
implicated in LTP
LTP
excitatory NMDA and AMPA implicated
lasting changes in strength of signal for learning and memory
glutamate LTP Mechanism
- presynaptic neuron fires AP, glutamate released and binds both AMPA and NMDA on postsynaptic membrane.
- AMPA rec. fun like excitatory postsynaptic rec. channel becomes permeable to both K and Na and NA influx depolarizes EPSP of postsynaptic cell
NMDA channels mediate Ca flux
when depolarized, Ca enters postsynaptic cell - Ca ions activate 2ndmessanger cascade with kinases and LTP
after LTP
subsequent APs will cause greater depolarization of postsynaptic membrane
NMDA receptors
excitatory postsynaptic channel receptor for glutamate
1. mediate Ca influx
2. excitotoxicity - injury spreads to adj. areas
when glutamate containing cells die, glutamate excessively stims AMPA and NMDA nearby causing accumulation of toxic conc. Ca and cell death
GABA
AA NT
INHIBITORY NT
Modified glutamate
can bind inotropic or metabotropic
sev binding sites
GABA receptors
iono or metabotropic
- inotropic increases Cl flux into cell = hyper polarization IPSP postsynaptic
GABA drugs
increase Cl flux thru GABA receptor
ethanol from alc target gaba
ethanol on GABA
stimulates GABA synapses and inhibits excitatory glutamate synapses
overall depression of activity
glycine
AA NT
inhibitory interneurons release
binds inotropic receptors on postsynaptic cells allow Cl to enter and prevent threshold for Pas
essential to maintain balance of excitatory and inhibitory activity
glycine antagonist
strychnine
imbalance of inhibitory and excitatory activity
glycine receptor
inotropic
allows Cl to enter cell
prevents threshold and AP
neuropeptides
2+ AAs w peptide bond
derived from large precursor proteins on ribosomes in cell body/dendrite far from release
either receptor
broken down by peptidases in membranes
neuropeptide synthesis
from 2+ AA on ribosome in cell body
large precursor protein invisible
peptidergic
neurons release 1+ peptide NT
endogenous opioids
neuropeptides
beta endorphin
dynorphin
enkephalin
opiates are analgesics - relieve pain
gases
nitric oxide, CO, HS
produced by enzymes in terminals in response to Ca entry and diffuse out of sites
purines
ATP and adenose
response to Ca influx
adenosine derived from ATP
lipid
membrane phospholipid-derived
eicosanoids like -
prostaglandins, endocannabinoids
in response to Ca entry and act as retrograde messengers - bind presynaptic
target of THC
CNS
NO nerves
ganglia
PNS groups of cell bodies
forebrain
cerebrum: right and left hemisphere
gray (cell bodies) and white matter (myelin)
corpus callosum and cerebral cortex
cerebral cortex
4 lobes with gyrus and sulcus
brain stem
pons medulla midbrain
hindbrain
cerebellum
movement, motor fxn
hypothalamus
homeostatic regulation
connect to pituitary gland - endocrine
PNS
somatic autonomic – PSNS and SNS
autonomic NS
enteric NS
2 neurons types
sympathetic NS neurons
neurons leave thoracic and lumbar regions
parasympathetic NS neurons
brain stem and sacral spine
craniosacral
sympathetic ganglia
close to spinal cord form 2 chains trunks
sympathetic NS activity
body wide
SNS and PSNS NT
acetylcholine
nicotinic receptors
SNS also Norepi
majority Ach receptor
nicotinic
catecholamines type
hormone released into the blood
adrenergic receptors affinity
epinephrine - B2
NORepi - a1
choroidplexus
ependymal cells produces CSF
blood brain barrier
astrocytes, TJs
fun of myelin
prevent K+ leak of ions out for successful AP communication
warburg effect
Cancer cells prefer/rely more heavily on anaerobic glycolysis over aerobic respiration, even in the presence of oxygen
can provide intermediates necessary for the biosynthesis of macromolecules
Help adapt to the hypoxic microenvironment
Acclimatization
effectiveness of existing systems can be enhanced by prolonged exposure to an environment change; improved function of homeostatic system
Reversible
norepinephrine affinity
a1
study the blood brain barrier
Immunofluorescence - label proteins with antibodies
neurovascular unit
endothelial cells, pericytes, astrocytes, and microglia
tight junction
comprised of occludin, adhesion, and junctional adhesion molecules as well as intracellular scaffold proteins. These transmembrane proteins are further linked to the cytoskeleton, establishing a high-resistance paracellular barrier to small ions
measure resting Vm
2 electrodes - 1 ref, 1 record.
effect of blocking electrogenic pump
Na would develop inside and cell would swell
voltage and patch clamp
manipulate membrane potential
2 electrodes to record Vm
add in current electrode
voltage clamp sets Vm anywhere
measure amount of current flow at different Vms
I = v/r
what to find from voltage clamp study
measure amount of current flow at different Vms
I = v/r
I = current conductance = opposite resistance
conductance
measure of current flow
depends on permeability
clamp experiment.
set vm
calc Ek and Nernst potential
measure
solve for conductance
capacitive flow
minus charge moves away from membrane
OR
ability for membrane stores electrical charge
DUE to lipids
over distance, drop in membrane potential?
resistance to flow
size of axon
myelination reduces loss
lose current to capacitance
capacitance
due to lipids, ability to store electrical charge
conductance is flow of charge current (proteins allow channels and permeability)
conductance depends on
inverse resistance
how many channels
open probability of channel
channel conductance
g
conductance of all channels
What is the number of charges necessary to produce the equilibrium membrane potential?
q=CV
length constant
Current decays with distance:
- resistance of cytoplasm
- resistance of PM
- charge that leaks out of axon (capacitative)
increased by increasing diameter of neuron and/or decreasing current leak by making membrane high resistance.
Cable properties of neurons permit electrotonic spread of local current from regions of depolarization to inactive regions.
