CH 3 Flashcards
House many of the cell bodies of neurons that use distinct NTs (DA/NE/5-HT/opioids) and send long projections that influence multiple brain regions; older brain regions; localized cell bodies
My/met/mesencephalon
Basal ganglia: dorsal / ventral striatum, limbi system
telencephalon
involved in motor control and action selection. most prominent nuclei include dorsal striatum (caudate/putamen) and ventral striatum (NAcc)
basal ganglia
plays a key role in motor learning and action selection; receives input from sensory/motor cortex and DA input from substantia nigra; refines movement and promotes efficient movement and inhibits inefficient ones
dorsal striatum
important for reward and motivated behaviours ; receives input from limbic system and DA input from the VTA
ventral striatum
Integrates emotional responses and regulates motivated behaviour and learning (feeding, fighting, fleeing, sexual behaviour); group of neurons just under the cortex that communicate with each other
limbic system
associated with establishment with new long-term memories and rational/spatial memory
hippocampus
coordinates various components of emotional responses (especially fear) through profuse connections with other brain areas - detects stimuli and sends signals to other areas
amygdala
interconnected with other structures, regulatory, feeding, sexual behaviour
hypothalamus
receives input from amygdala and hippocampus - moves toward or away from stimulus
Nucleus accumbens
goes down the middle of the brain
prefrontal (cingulate) cortex
partitioning of different cortical regions based on crytoarchitecture, or histological structure and organization of cells (e.x. packing of neurons, or layers of neurons)
brodmann’s areas
mediate voluntary and well learned motor sequences
primary/secondary motor cortex
critical for making decisions, planning actions, evaluating different strategies; executive function, coordination of different system, form reciprocal inhibitory relationships with limbic system and striatum, organizes effective patterns of behaviour
prefrontal cortex
All _____ regions contain receptors for numerous NT systems affected by _____ drugs. Relative concentrations of NT varies across _______. One may be affected more with a smaller _____ of drug depending on receptors and NT concentration
telecenphalon, psychoactive, regions, dose
terminal connects with a dendrite of the postsynaptic cell; the most common type of synapse, usually connected to dendritic spines, but sometimes to dendritic shafts
axodendritic
the closer the synapse is to the ____ _____, the more effect of ____ _______, because it doesn’t have to travel far to the axon hillock where the action potential is ______
cell body, electrical potential, generated
axon terminal forms connections with the neuron cell body, resulting in a very powerful synapse and greater depolarization/hyperpolarization
axosomatic
axon synapsing on another axon terminal which can either reduce or enhance NT release of receiving terminal; work via heteroreceptors
axoaxonic
reduction of NT release of presynaptic cell to postsynaptic
presynaptic inhibition
increase of NT release of presynaptic cell to postsynaptic
presynaptic facilitation
receptors on axon terminals that respond to transmitters different from those released by those terminals; respond to NTs released at axoaxonic synapses
heteroreceptors
An individual neuron can make one or several different ______, and ___ can hold one or both of them. ____ and ____ can be released from the same cell
NTs, vesicles, glutamate, GABA
Most NTs are made in ________ but peptides are made in the _____ and then transported to terminals. Many peptide transmitters reside in terminals that also contain _______ small molecule transmitters
terminals, soma, classical
small patterns of firing will result in ____ type of NT, while different patterns of firing will result in firing of additional _____
one, peptides
classical neurotransmitters
amino acids, monoamines, acetylcholine purines
amino acids
glutamate, GABA
monoamines
DA, NE, 5-HT
acetylcholine purines
ATP, adenosine
nonclassical NTs
neuropeptides, lipids, gasses
neuropeptides
endorphins, enkephalins, corticotropin-releasing factor, orexin/hypocretin, BDNF
lipids
anandamide, 2-arachidonoylglycerol
gasses
NO, CO, H2S
10 steps of neurotransmission
- NT is synthesized and stored in vesicles 2. action potential invades presynaptic terminal 3. depolarization causes voltage gated Ca2+ channels to open 4. Ca2+ enters terminal through channels 5. Ca2+ causes vesicles to fuse with presynaptic membrane 6. NT is released into synaptic cleft via exocytosis 7. NT binds to receptor in postsynaptic membrane 8. opening / closing of postsynaptic channel or activation of second messenger 8. postsynaptic currents excite or inhibit the neuron 9. vesicle membrane gets retrieved/recycled via endocytosis
causes a very fast and distinct signal in the postsynaptic cell; do not travel far, and affect only one small part of the neuron
neurotransmitter
may enhance, reduce, or prolong the action of another NT, have differential effects, and does not change the excitability of a neuron at rest by much; not fast
neuromodulators
when neuromodulators diffuse away from the site of release to influence other cells and many parts of the cell; works on extrasynaptic receptors
volume transmission
receptors that are not tightly localized to presynaptic terminal
extrasynaptic receptors
many classical Nts can act as _____ depending on the specific receptor they interact with
neuromodulators
in general _____ and _____ firing releases more NT than ______ and _____ firing, due to better activation of ____ channels. Many neurons that use classical NTs switch to burst firing mode in response to motivationally or _____ relevant stimuli
higher rates, burst, lower rates, continuous, Ca2+, emotionally
receptors for the same NT released by the neuron
autoreceptors
receptors that are activated by NTs and inhibit further NT release by hyperpolarizing the terminal so that the next transmitter release is very little
presynaptic terminal autoreceptors
receptors that reside on cell bodies/dendrites that when activated, slow firing, reduce transmitter release by chemical released by cell body
somatodendritic autoreceptors
the processes of breaking an NT molecule in half after it pops off the post synaptic receptor; involves an enzyme embedded in the brain
enzymatic degradation
when transporters actively transport the NT to a place outside the synapse, or when NT is taken up by presynaptic neurons
reuptake
reuptake can occur by nearby ______, or mediated by _______ through active transport. However, some transporters are “sloppy” and can uptake other types of NTs with similar ____ _____
astrocytes, transporters, chemical structures
Almost all NTs have more than one receptor ______, which can vary in expression across or within brain regions. All subtypes bind the same ligand, but with different _______, such that ____ concentration of subtypes are needed for low affinity subtypes. Sometimes, different receptor subtypes can exert ______ cellular effects via different _____ ______.
subtype, affinities, greater, opposite, 2nd messengers
Some NTs only work on _______ receptors such as DA and ____, while others can work on these and ionotropic receptors, such as ____, GABA and ______
metabotropic, NE, Glu, ACh
Ionotropic receptors consist of ____ subunits with an _____ channel in the centre. It is embedded in the ______. Some ______ the cell by conducting Na+, while others do so by conducting ______. Some conduct _____ leading to hyperpolarization
4-5, ion, membrane, depolarize, Ca2+, Cl-
Metabotropic receptors act more slowly, and the effects last ______. It winds around the membrane several times and works by activating ____ proteins.
longer, g
G proteins inhibit/activate _______, or stimulate / inhibit _____ ______
ion channels, effector enzymes
enzymes that synthesize or break down second messenger molecules
effector enzymes
molecules inside cell that activate protein kinases that phosphorylate other proteins (turn on or off protein)
second messengers
_____ of ion channels and receptors can change their function. The same processes for nuclear proteins can turn _____ expression on/off (long term plasticity)
phosphorylation, gene
a second messenger pathway that stimulates protein kinase A; channels
cyclic adenosine monophosphate (cAMP)
breaks down a phospholipid in the cell membrane, liberating two 2nd messengers: diacylglycerol (DAG) and inoitol triphosphate (IP3)
phosphoinositide
DAG and IP3 increase concentration of _______ ions in the postsynaptic cell and activate _____ _______ _______. They are controlled by receptors for ACh, NE, and ______
Ca2+, protein kinase C, 5-HT
DAG and IP3 increase concentration of _______ ions in the postsynaptic cell and activate _____ _______ _______. They are controlled by receptors for ACh, NE, and ______
Ca2+, protein kinase C, 5-HT
If a drug acts a ______ it increases the rate of synthesis and activity, or it inhibits the ______ involved in synthesis to reduce transmitter levels
precursor, enzyme
precursor to DA
L-DOPA
5-HT precursor that helps with sleep
tryptophan
inhibits tyrosine hydroxylase, involved in making DA and NE; can induce depressive like symptoms
alpha-methyl-para-tyrosine (AMPT)
inhibits tryptophan hydroxylase, involved in synthesizing 5-HT
para-chlorophenylalanine
Drugs can block the storage of NT in ______, which exposes the NT to _______ _______ within the cell. An example is ______, which disrupts storage of _____, NE and 5-HT in vesicles by blocking ____ ________, causing depressive side effects
synaptic vesicles, enzymatic degradation, reserpine, DA, vesicular transporters
Drugs can stimulate release of NT by reversing _____ ______. An example is _____ which takes free floating molecules inside the terminal and pushes them outside into the _______ through a non vesicular mechanism. Furthermore, NT released through regular synaptic transmission is ______ because regular transporters are not doing their job
uptake transporters, amphetamine, synapse, abundant
stimulates the release of DA and NE through reversing uptake transporters
D-amphetamine
A decongestant that works like amphetamine, which is preferential for NE and has less BBB permeability; constricts blood vessels in the nose, but long term use leads to downregulation of receptors
pseudoephedrine
Drugs can directly block NT release. An example is ___ ____, which interferes with synaptic vesicle release of ______. It binds to proteins in the release point of the _______ _______, and prevents vesicles from binding and releasing NT. This results in face stretching but also impairment of ______ and ______
botulinum toxin, ACh, neuromuscular junction, respiration, movement
Drugs can also stimulate ______, or block ______, the postsynaptic receptor.
agonist, antagonist
An agonist that stimulates the micro-opioid receptor
heroin
an antagonist that blocks adenosine receptors
caffeine
an antagonist that blocks ACh muscarinic receptors - receptors in the brain and body involved in memory and congestion
atropine
A drug can also stimulate or block an _______. An autoreceptor agonist such as ______ and ______, reduces transmitter levels. An autoreceptor antagonist such as _____ increases transmitter levels
autoreceptor, Clonidine, 8-OH-DPAT, yohimbine
a NE autoreceptor agonist
clonidine
a 5-HT autoreceptor agonist
9-OH-DPAT
A NE autoreceptor antagonist which causes stress and anxiety like symptoms
yohimbine
a 5-HT autoreceptor antagonist
pindolol
Drugs can block the enzyme involved in NT _______, prolonging or enhancing the NT action. Examples are ____ which blocks acetyl-cholinesterase, that breaks down _____, and______ which blocks MAO which breaks down monoamines. However, these effects do not produce as rapid of effects as if you block _____
breakdown, physostigmine, ACh, phenelzine, reuptake
Drugs can block ______ transporters enhancing NT action. Examples are ____ which blocks the transporters for DA, ____ and _____, and ______ antidepressants, which block the ____ transporter, causing it to build up in the synaptic space
uptake, cocaine, 5-HT, NE, tricyclic, NE
additional binding sites other than the main one of the receptor
allosteric sites
molecules that bind to additional sites on the receptor and alter receptor functioning; can have a positive or negative effect on receptor signaling
allosteric modulators
Allosteric modulators have _____ effects on their own, as they can only _____ the effects of an agonist. Certain _____ hormones can act as allosteric modulators, which _____ ____ how much the receptor is turned on by the agonist. For an ionotropic receptor, the ion channel may _______ larger or smaller, while for a metabotropic receptor, it could be that the _____ ___ stays for longer, or a modulation in ______. Some _____ _____ are negative allosteric modulators
no, modulate, endogenous, fine tunes, open, second messenger, enzyme, inverse agonists
pyramid shaped cells that function as the principle output neurons of the cerebral cortex
pyramidal neuron
Neurotransmitter receptors and proteins on the postsynaptic side of the cleft
postsynaptic density
the connection point between a neuron and muscle
neuromuscular junction
both chemical and electrical transmission occur between neurons
mixed synapses
when two neurons are connected by specialized proteins that permit the flow of electric current from one cell to the other
electrical synapse
tight cell-to-cell synaptic interactions
wiring transmission
specialized release sites near the postsynaptic cell - only vesicles located here can release NT
active zones
the NTs that are immediately released
readily releasable pool
The NTs further from active zones that can be called upon for release when the neuron is firing for a prolonged period of time
reserve pool
the readying of vesicles for NT release once Ca2+ is there
priming
when an ionotropic channel remains closed even though a ligand is bound and must be resensitized before it can be activated again
desensitization
a second messenger that is regulated by NO, activates protein kinase G and is inactivated by phosphodiesterase
cyclic guanosine monophosphate (cGMP)
a kinase activated by Ca2+ that help activate PKC
calcium calmodulin kinase II
receptors that mediate the action of neurotrophic factors
tyrosine kinase receptors
proteins that stimulate survival and growth of neurons during early development and are also involved in neuronal signaling
neurotrophic factors
When various experiences can alter the strength of synaptic connections, resulting in both functional and structural changes; dendritic length, branching patterns, and dendritic spines can all be altered by drugs
synaptic plasticity
