Lecture 19 Flashcards
a ________ is a functional junction between neurons
synapse
- information sending neuron=
- information receiving neuron=
- presynaptic neuron
- postsynaptic neuron
the _________ _______ is between the presynaptic and postsynaptic cell while the ________ ________ are on the dendrites of the postsynaptic cell
synaptic cleft; receptor proteins
-chemical messengers that get released into the synaptic cleft are called ___________
- they are stored in ________ ________ in the terminal buttons of the presynaptic cell
- neurotransmitters
- synaptic vesicles
_________ channels located at the axon terminal of the presynaptic neuron are ______- gated which means that they will open in response to a change in membrane potential
calcium; voltage
Two types of synapses:
1.
2.
- electrical
- chemical
Electrical synapse
- presynaptic and postsynaptic neurons are directly connected through a channel called “_________ ________”
- _____ diffuse directly from 1 cell into the next
- much _________ but CANNOT integrate information
- Gap junction
- ions
- FASTER
Chemical synapse
- separated by a physical space= _________ ______
- ALLOWS for integration for information from multiple ________
-most ________ in the nervous system
- synaptic cleft
- neurons
- COMMON
3 amino acids that act as neurotransmitters (NTs)
1.
2.
3.
- Glycine
- Gamma(y)-aminobutryic acid (GABA)
- Glutamate
5 types of Monoamines= ______________ NTs
1.
2.
3.
4.
5.
- they contain a _______ group in their chemical structure
biogenic amines
1. Dopamine
2. Epinephrine
3. Norepinephrine
4. Histamine
5. Serotonin (5-HT)
- amine
The three catecholamines (NTs)
1.
2.
3.
-these are derived from the amino acid _______
- Dopamine
- Epinephrine
- Norepinephrine
- tyrosine
Neuropeptides=
1.
2.
peptides neurotransmitters
1. Substance P
2. Opioid peptides
____________ is the rate-limiting enzyme that synthesizes dopamine while ___________ turns DOPA into dopamine
Tyrosine hydroxylase
DOPA decarboxylase
Another name for norepinephrine and epinephrine=
noradrenaline
adrenaline
Two major enzymes that are responsible for catecholamine CATABOLISM in the brain:
1.
2.
- Catechol-O-methyltransferase (COMT)
- Monoamine oxidase A (MAO-A)
Steps that lead from the AP arriving at synaptic terminal to the release of NTs
1. AP arrives at ____________
2. Voltage-gated _____ channels open (due to __________ from arrival of AP) and it enters the axon terminal
3. ____- entry causes NT-containing _______ ________ to release their contents by exocytosis
4. NT diffuse across the synaptic cleft and binds to _____-gated ion channels on the postsynaptic membrane
- axon terminal
- Ca2+; depolarization
- Ca2+ ; synaptic vesicles
- ligand
Glutamate= __________ neurotransmitter
- this means it will produce _________ (make more positive) on the postsynaptic membrane
GABA= ________ neurotransmitter
-this means it will produce _________ (less likely to generate an AP)
excitatory
- depolarization
inhibitory
- hyperpolarization
EPSP=
IPSP=
both _____ ______ potentials
produced in the ____________
- Excitatory Postsynaptic Potential
- Inhibitory Postsynaptic Potential
- local graded
- postsynaptic terminal
resting membrane potential (RMP) = around _____ mV
threshold voltage to trigger an AP in a neuron= usually around _____ mV
-70 mV
-55 mV
Ions responsible for inducing an EPSP=
- these ions go inside (=_______)
Ions responsible for inducing an IPSP=
- these ions go outside (=_______)
- the other ion go inside (=______)
Sodium Na+
- influx
Potassium K+; Chloride Cl-
- efflux
-influx
GABA-A receptor
- the alpha, beta, gamma letters on the GABA-A receptor represent….
different proteins that form the receptor, they are sometimes referred as subunits
GABA binds to a site near the junction of alpha and beta subunits, and this causes conformational changes that open the _______ ion channel (influx of ions) which leads to neuronal membrane ___________
chloride; hyperpolarization
3 ways for concluding synaptic transmission
1.
2.
3.
- Enzymatic degradation
- Diffusion
- Reuptake by presynaptic neurons
Examples of enzymatic degadation
COMT and MOA-A —> degrades biogenic amines
Acetylcholinesterase–> degrades acetylcholine
Example of reuptake by presynaptic neuron
SERT= serotonin transporter
4 dopaminergic pathways in the brain
1.
2.
3.
4.
- Nigrostriatal
- Mesocortical
- Mesolimbic
- Tuberofundibular
The nigrostriatal pathway connects the __________ located in the midbrain with the _______ (caudate and putamen), within the basal ganglia
substantia nigra; striatum
The nigrostriatal pathway is responsible for _____ __________
- abnormalities that would arise form the impairment of structures associated with the nigrostriatal pathway=
- decreased activity= __________ (parkinsonian symptoms)
- increased activity= __________ (movement disorders)
motor movement
- motor disorders
- hypokinetic
- hyperkinetic
the term “kinetic”=
“of motion” (movement)
a mental disorder characterized by disturbances in thinking, emotions, and behavior, often leading to impaired perception of reality
- positive symptoms=
- negative symptoms=
Schizophrenia
- hallucinations
- apathy, lack of motivation
2 pathways related to schizophrenia
1. ____________ pathway= cognitive and negative symptoms
2. ___________ pathway= positive symptoms
- Mesocortical
- Mesolimbic
VTA= ___________ located in _______
Ventral Tegmental Area; midbrain
The mesocortical pathway connects the _______ with the _________ _______ and it controls……
VTA; prefrontal cortex; emotions and affect, planning, judgement
The mesolimbic pathway connects the ______ with the ______ ______ (part of the limbic system) and it controls…..
VTA; nucleus accumbens; motivation and reward
____________ of dopamine receptor-1 (D1) in the _________ pathway contributes to __________ symptoms of schizophrenia
dysfunction; mesocortical; negative
_____________ of the D2 receptor in the __________ pathway contributes to _________ symptom of schizophrenia
hyperfunction; mesolimbic; positive
The hypothalamic nucleus that is considered the “infundibular nucleus”=
- the tuberoinfundibular pathway projects from the __________ to the anterior ________ ________
arcuate nucleus
- hypothalamus; pituitary gland
The tuberoinfundibular dopaminergic pathway causes the inhibition of __________ release
prolactin
neuroplasticity=
synaptic plasticity=
- the ability of the brain to change, or rewire, throughout a person’s life
- the process of neuroplasticity occurring at the single-cell level (individual synapse)
Two factors that determine whether changes in synaptic strength are temporary or long-lasting
intensity and reoccurrence of the signal the synapse receives
Temporary= ____________ memory
Long-lasting= ___________ memory
short-term
long-term
Two methods by which the neuron can temporarily increase its synaptic strength
1.
2.
- increasing the amount of NTs released
- Increasing the number of postsynaptic receptors available
Two types of long-lasting neuroplastic changes?
1.
2.
- Structural
- Functional
2 examples of structural neuroplastic changes
1.
2.
- _________ or _________ activities are required to produce structural neuroplastic changes
- growth of new dendritic spines and synaptic connections
- Changes in cortical areas
- strong; sustained
neurons may adopt a new function when they are sufficiently stimulated (after a stroke) which is a _________ change, which are ___________ changes
functional; long-lasting
what is a stroke?
sudden disruption of blood flow to the brain
The __________ is considered a “memory-forming center”
Long-term memories are consolidated and storage in various areas of the _______ _______
hippocampus
cerebral cortex
LTD=
- is a long-term _________ of a synaptic connection
- it allows for _________ connections to be LOST and makes synapses that have undergone LTP that much ________ by comparison
LTP=
- is a persistent __________ of a synaptic connection
- base to create ____________
Long-term depression
- weakening
- unimportant
- stronger
Long-term potentiation
- strengthening
- new memories
LTP is caused by….
high-frequency signals (strong experience)
or
repeated stimulations (studying, revising)
Synaptic plasticity follows the “___________________” rule: frequently used synapses are strengthened while rarely used connections are eliminated
use it or lose it
AMPA and NMDA receptors are located on the same ___________ neuron and they recognize the NT _________
postsynaptic; glutamate
The mechanism of LTP in the hippocampus
1. Glutamate released first activates ______ receptors which causes _____ influx
2. Frequent ______ receptors stimulation by glutamate will cause the postsynaptic neuron to depolarize even more, causing the release of _______ from the NMDA-R allowing ______ to flow in through it
3. This _____ influx initiates cellular mechanism that cause more ________ to be inserted into the neuron’s mb
4. Now, the postsynaptic cell is more _______ to glutamate because it has more receptors to respond to it (this type of change is _________)
- Ca2+ also promotes the _____________________ which is considered long-lasting change
- AMPA; Na+
- AMPA; Mg2+; Ca2+
- Ca2+; AMPA receptors
- sensitive; temporary (short-term)
- growth of dendritic spines
Mechanism of LTD at the glutamatergic synapse
- low firing rate of the presynaptic neuron—> few ________ molecules
which causes intracellular Ca2+ ions that stimulate ________ of AMPA receptors
- LTD induces dendritic spine _________ and synaptic ______ therefore memory ______
- glutamate; endocytosis
- shrinkage; loss; loss
