MIDTERM 2 Flashcards
(183 cards)
1
Q
What are ions?
A
Elements or molecules that are charged
2
Q
How does the movement of ions affect neurons?
A
Changes their voltage/electric potential
3
Q
What are the major ions for neuron signaling?
A
Sodium (Na+)
Potassium (K+)
Chloride (Cl-)
Calcium (Ca2+)
4
Q
True or false: there is an equal concentration of ions inside and outside the cell
A
False
5
Q
What is the imbalance of ions inside and outside of the cell called?
A
A concentration gradient
6
Q
What is the purpose of a concentration gradient?
A
They are the major driving force for electrical signaling
7
Q
Why are neurons like “bananas in the sea”
A
Containers of K+
In solution of salt (Na+ and Cl-) and Ca2+ is there as well
8
Q
Is a high concentration of sodium (Na+) intracellular of extracellular?
A
Extracellular
9
Q
Is a high concentration of potassium (K+) intracellular of extracellular?
A
Intracellular
9
Q
Is a high concentration of chloride (Cl-) intracellular of extracellular?
A
Extra cellular
9
Q
Is a high concentration of calcium (Ca2+) intracellular of extracellular?
A
Extracellular
10
Q
True or false: cellular membranes allow ions to move in and out of the cell
A
False
11
Q
How do ions pass across the membrane?
A
They depend on specialized proteins called “channels”
12
Q
What are ion channels
A
Proteins that are folded into a spiral that leaves a pore in the middle for ions to pass through
13
Q
How is electrical signaling in the ion channels primarily controlled?
A
Opening and closing the channels
14
Q
True or false: channels are specific for a given ion
A
True
15
Q
True or false: A K+ can pass through a Na+ channel
A
False: Na+ only passes through Na+ channels
16
Q
What are the three major types of ion channels?
A
Leak
Ligand-gated
Voltage-gated
17
Q
Which ion channels is always open?
A
Leak channels
18
Q
What is the importance of a leak channel?
A
They maintain the membrane potential (voltage) of the cell
Keeps electrical environment constant during rest periods
19
Q
What ion channels are closed by default, causing ions to be unable to flow in/out?
A
Ligand-gated channels
Voltage-gated channels
20
Q
What is the structure of a ligand-gated channel?
A
Ligand binding site on the extracellar (outside) side of the protein
21
Q
What is a ligand
A
A chemical signal that binds to the binding site of a channel/receptor
Ex: neurotransmitters, hormones, axon guidance cues
22
Q
What happens when a ligand binds to a ligand-gated channel?
A
The protein will shift around, causing the channel to open
Ions will flow in/out of the channelT
23
True or false: each channel has its own specific ligand, different ligands will not activate the cell
True
24
What is the importance of a ligand-gated channel?
Imp for synaptic signaling in the dendrites
25
What is the structure of a voltage-gated channel?
They have a specialized segment of the channel protein on the intracellular (inside) of the neuron, which is a voltage sensor
When the cell becomes positive enough, the voltage sensor detects it, causing the channel to open Ions
26
True or false: not all neurons are charged
False
All charged due to the imbalance of +/- ions in the cell
27
What is the electrical charge of a neuron (the cell’s voltage) called
The membrane potential
28
Maintained by leak channels, what is the default voltage that neurons will return to over time?
The resting membrane potential (Em)
29
What is the typical charge of a resting membrane potential (Em)
-70 mV
30
Ions cannot move across the membrane on their own so how will the membrane potential change?
Ions flow in/out of the cell due to the opening and closing of channels
31
True or false: ions will always move down their concentration gradient
True
32
How does the concentration gradient flow
High to low concentration
33
Would Na+ move in or out of the cell when the ion channels open?
Na+ has a high extracellular (outside the cell) concentration
When Na+ channels open, Na+ will move down its concentration gradient = flows INTO the cell
34
Will the cell become more positive or more negative when Na+ flows into the cell?
Na+ has a positive charge
= as it flows into cell, will become more positive
35
What is depolarization?
A cell becoming more positive
36
What is an excitatory post synaptic potential (EPSP)?
When a cell becomes more positive
Called this because changes in membrane potential is typically recorded from a cell that was stimulated at a synapse
37
What happens when Na+ channels open?
The cell depolarizes because the positive Na+ ions flow into the cell, causing an EPSP
38
Graph an EPSP plot
39
How do EPSPs change the voltage?
Temporarily make the cell more positive
Returns to baseline because of open leak channels
Allows cell to maintain a baseline when not stimulated
40
Will Cl- flow in/out of the cell and will that cause the cell to become more + or -
Cl- will flow into the cell
Cl- will cause it to become more negative
41
What is it called when a cell becomes more negative
Hyperpolarization
42
What potential is correlated with hyper polarization?
Inhibitory Postsynaptic Potential (IPSP)
43
Graph an IPSP plot
44
How do IPSPs change the voltage?
Temporarily make the cell more negative
Returns to baseline because of open leak channels
Allows cell to maintain a baseline when not stimulated
45
True or false: K+ is a positive ion so its cell becomes more positive when K+ channels are open
False
K+ is positive but the cell becomes more negative
46
Why do K+ cells result in hyperpolarization?
When K+ channels are open, its ions move down its concentration gradient
Positive charges leave, so cells become more negative
47
True or false: even though Na+ and K+ are both positive ions, they have inverse effects on the membrane
True!
Na+ depolarizes
K+ hyperpolarizes
48
True or false: Ca2+’s concentration gradient is weak
True
Very little Ca2+ flows into the cell = does not depolarize much
49
True or false: while it does not change the membrane potential much, Ca2+ is the most influential ion for neurons
True
Activates protein function
50
What is the only ion that activates proteins to do functions (ex: plasticity, muscle contraction, gene expression)
Ca2+
51
What do EPSPs typically form on cells
Synapses on the dendrites of the cells
Causes them to depolarize (becoming more positive)
52
What happens to the positive charges of the EPSP after the synapses form
Doesn’t stay in dendrites -> diffuses through the cell becomes
Travels from dendrite -> cell body -> axon hillock
53
What happens if the axon hillock becomes positive enough?
The neuron will fire an AP
54
What is the AP threshold?
the amount of positivity needed to fire an EP
55
True or false: a single EPSP is a very large change in membrane ponytail
False
56
True to false: EPSP will slightly decay as it travels to the axon hillock
True -> will not have enough charge to reach the axon hillock to fire an AP
57
Why are single EPSPs not very powerful?
prevents neurons from being overly sensitive to spontaneous firing
Neurons depend on summating multiple EPSPs to fire an AP
58
What are the two forms of EPSP summation?
Temporal
Spatial
59
What is temporal summation?
Two (or more) EPSPs on the same dendrites happen in quick succession
EPSP will summate their depolarization and travel to the axon hillock… only possible when they occur close in time or will return to Em
60
What is spatial summation?
Two (or more) EPSPs on the same dendrites happen at the same time at multiple dendrites
EPSPs from one dendrite will summate on the EPSP from another dendrite
61
True or false: temporal and spatial summation are mutually exclusive
False
Both used in tandem to make the neuron positive enough to cause an AP -> allows integration of information from very active axons
62
What is an AP?
A large charge of membrane potential that travels down an axon
Conveys info from the cell body to the synaptic terminal
63
How do APs work?
Large depolarization reaches synaptic terminal -> stimulates neurotransmitter release -> causes neuron to communicate with another cell
64
True or false: action potentials are binary processes
True!
All or nothing
65
How is it decided if APs will fire?
If the membrane potential reaches the AP threshold
66
True or false: APs for a given neuron will always be the same amplitude
True
But amplitudes may be different across neurons
67
How do neurons communicate?
Changing the number of APs that are fired because amplitude of all APs for a cell are the same
Firing rate = number of APs fired per second
68
Most cells have a baseline spontaneous firing rate. How does this affect AP firing?
Can increase or decrease rate of AP firing to carry info
69
AP will fire when a neuron depolarizes to
-55 mV
Will not fire if it’s less than -55 mV
70
How do EPSPs affect AP
Increases likelihood of firing an AP as it gets closer to AP threshold
Typically depolarization
71
How do IPSPs affect AP
Decreases likelihood of firing an AP as it prevents it from reaching the threshold
Typically hyperpolarization
72
How are voltage-gated Na+ channels and voltage-gated K+ channels similar
Both are ion channels that use chemical gradients to move ions across the membrane
Both voltage-gated and open when the neuron depolarizes enough
Ion specific
Essential for APs to happen
73
What two ion channels are AP dependent on
Voltage-gated Na+ channels
Voltage-gated K+ channels
74
What is the opening voltage for Na+ and K+ channels
Na+: -55mV
K+: -45mV
75
What is the effect on membrane potential for Na+ and K+ channels
Na+: positive
K+: negative
76
What is the opening/closing speed for Na+ and K+ channels
Na+: faster
K+: slower
77
Is there an inactivation mechanism for Na+ and K+ channels
Na+: yes
K+: no
78
When are membrane potentials open/closed
Open: when membrane potentials are greater than threshold
Closed: when membrane potentials are below threshold
79
How does Na+ channel inactivation work?
Channels becomes inactivated after being open for a short of time
Protein has a specialized “ball and chain” segment on intracellular side -> moves into channel pore, clogging it -> inactivates channel
= no ions can flow through, regardless of membrane potentials
Ball and chain will remove itself from the pore over time
80
Draw an AP waveform and include: resting membrane potential (Em), AP threshold, rising phase, falling phase, and refractory period. Identify which ions have the greatest amount of movement across the membrane and which are open/closed/inactivated
81
What is the refractory period
A period of time that the neuron is unable/very unlikely to fire another AP
82
What are the two phases of refractory periods period
Absolute
Relative
83
What is the absolute refractory period? Why does it occur?
When the neuron is physically unable to fire another AP
When Na+ channels are open/inactive due to the ball and chain clogging the pore
= cannot fire another AP
84
Following the falling phase, how do Na+ channels transition?
From inactivated to closed
85
What is the relative refractory period
The neuron is able to fire another AP, though unlikely
Follows the absolute refractory period
Cell is hyperpolarized = needs a very strong stimuli to fire another APTr
86
True or false: APs get fired at the axon hillock and passively travel down teh axon
False
APs are active processes which propagate from the axon hillock to the synaptic terminal
87
How does the structure of an AP allow it to be actively propagated along the whole axon, making it able to fire APs at any point of it?
Axon is filled with Na+ and K+ voltage-gated channels
88
What is the process of APs (AP propagation)
Start at the axon hillock -> depolarization will cause the adjacent region of the axon to hit the AP threshold -> adjacent region fires AP -> refining AP along whole axon
89
What is AP propagation (in)effective for
Effective for very short axons
Ineffective for long axons because they depend on myelin
90
True or false: segments of myelin have no Na+ or K+ voltage-gated channels
True
91
APs cannot be propagated in myelin segments so where is filled with Na+/K+ voltage-gated channels?
The nodes of ranvir
92
Where do APs fire and how/where does it travel
The axon hillock
Depolarization will passively travel through the myelin insulated axon
Arrives at the node of ranvir
Another AP fired at the node -> depolarization passively travels along the next myelin insulated segment
APs will jump from node to node (saltatory conduction)
To the synaptic terminal -> release of neurotransmitters
93
What is saltatory conduction?
When APs travel down the axons are refired at each node
94
What is a synapse
The location where a presynaptic axon meets a postsynaptic cell
95
Which part of the synapse primarily sends info to the postsynaptic cell
The presynaptic cell
96
What are the two categories of synapses
Electrical
Chemical
97
What forms tunnels between cells that allow ions to freely flow between cells, similar to leak channels for electrical synapses
Gap junctions
98
What are the characteristics of electrical synapses?
Pre and postsynaptic cells are physically touching
Extremely fast signaling
Ions quickly flow from one cell to another with no gating mechanism
AP depolarization travelling down axon will directly carry over to next cell
Info passing between cells cannot be modulated, unlike chemical synapses
99
What are the characteristics of chemical synapses?
Pre and postsynaptic separated by synaptic cleft: microscopic gap between cells
Neurotransmitters are released from the presynaptic cell
NTs then passively drift across the synaptic cleft
NTs bind to NT receptors on the postsynaptic cell membrane
NT receptors will perform some type of cellular function when they bind = change in membrane potential, protein activation, gene expression
100
Which synapse is more common: electrical or chemical
Chemical: almost all synapses in the nervous system are chemical
101
Which synapse is faster: electrical or chemical
Electrical is rly fast
Chemical is far slower
-> need to release NTs, let them drift, and then activate receptors
102
Which synapse is more dynamic: electrical or chemical
Chemical= info passing between cells is modulated
103
Where does info get converted from an electrical signal (AP) to a chemical signal (NT)
The end of an axon/axon bouton
104
What are the important components of synaptic transmission
NT vesicles
SNARE complex proteins
Ca2+ voltage-gated channels
NT reuptake proteins
105
What are NT vesicles
Spheres made of the same material as the cellular membrane and filled densely with NTs
Vesicles will contain only one type of NT, each vesicle contains the same amount of NTs vesicles
106
How does the structure of a NT vesicle allow it to quickly release NTs into the cleft
The NT vesicles are attached to the inside of the cellular membrane that is facing the synaptic cleft NTs bind
Additional NT vesicles are not attached to the membrane; form a reserve pool that are ready to be attached to the membrane
107
What is the structure of the SNARE complex?
Vesicles are secured to the intracellular side of the membrane with SNARE complex proteins
108
What is the SNARE complex responsible for
securing the vesicles to the membrane, causing the NTs to be released into the synaptic cleft
109
What is the SNARE complex attached to
Attached to the NT vesicles and membrane
Tightly secures the vesicle against the inside of the cellular membrane
110
What is the SNARE analogous to and why (explain the process)
A clip that is held open, and ready to close
= locks proteins into a high stress position by Ca2+ sensor proteins
When it detects Ca2+ in the cell, the proteins will be released from the SNARE complex -> allowing proteins to clamp close and expel their stored energy -> applies force on the vesicle onto the cellular membrane -> forces vesicle to fuse with membrane dye to the force -> NTs released into the synaptic cleft
111
What are some characteristics of the Ca2+ voltage-gated channels
In the synaptic terminal
Opens quickly when the membrane potential reaches ~0mV
No inactivation mechanism
112
What are the steps of synaptic transmission
1) AP travels down from the axon into the synaptic terminal
2) synaptic terminal greatly depolarizes, activating Ca2+ voltage-gated channels
3) Ca2+ rushes into the synaptic terminal greatly
4) SNARE complex Ca2+ sensors detect an increase of Ca2+ in the cell
5) SNARE complex forces the NT vesicles to fuse with the membrane -> forces NT into cleft
6) NT will drift across the synaptic cleft to bind to the receptors on the postsynaptic cell, causing some type of cellular function
7) NTs are cleared out of the synaptic cell and the postsynaptic cell stops responding
113
What is the purpose of synaptic cleft clearance
Nervous system will clear out synaptic cleft of NTs quickly to prepare the synapses for the next wave of NTs
114
What are the three methods of synaptic cleft clearance
NT reuptake proteins
Degradation
Diffusion
115
How does NT reuptake work (synaptic cleft clearance)
Proteins in the presynaptic cell bring NTs back into the cell
NTs can be:
- recycled to be reused
-broken down and used for other processes
116
How does degradation work (synaptic cleft clearance)
NTs are broken down by enzymes free floating in the synaptic cleft
Will clear out the NTs over time as they bind and break down the NTs
117
How does diffusion work (synaptic cleft clearance)
NTs will float out of the synaptic cleft
-> taken up by neighboring astrocytes
118
How will synaptic cleft clearance work
Clearance processes will not significantly affect NT signaling in a healthy system
NTs released in large quantities so many NTs will interact with a postsynaptic cell before they are cleared out
119
What are NT receptors
Proteins activated when a NT binds to their NT binding site
120
True or false: receptors are ligand specific
True
Activated by only one specific NT but other substances activate receptors by mimicking a given NT
121
How do NT receptors work
NTs will repeatedly bind and unbind with receptors, repeatedly turning functions on/off
Repeat until all NTs are cleared from the synaptic cleft
122
What are the two classes of NT receptors
Ionotropic
GPCR
123
True or false: GPCR are more simple of the two NT receptors
False
Ionotropic are
124
What are some qualities of an Ionotropic receptor
Ligand-gated ion channels and NT binding sites are a part of the same protein
NT binds to their receptor -> change in membrane potential (=EPSP, IPSP)
Does not influence cellular function in other ways
125
What are some qualities of a GPCR receptor
Uses a G protein-coupled receptor
Still have a NT binding site, but no ion channels built into the same protein NT
When NTs bind to GPCR, G proteins detach from the internal side of the receptor protein
G proteins will activate other proteins to influence cellular processes
126
How do GPCRs affect cellular processes
Open ion channels, changing membrane potentials
Influence other proteins
Influence gene expression
Can also influence membrane potentials but does not directly contain the ion channels like ionotropic receptors do: activates separate ion channels with the G protein
127
Compare ionotropic and GPCR receptors
GPCRs can also influence membrane potentials but do not directly contain the ion channels like ionotropic receptors, activating separate ion channels with the G protein compare
GPCR receptor activation is slower
GPCRs typically result in long term influence of neural activity
128
True or false: the same NT can bind to a wide range of different receptors
True
129
True or false: the same NT can have inverse effects on cells based on the type of receptors that the postsynaptic cells have
True
130
What are the two pathways of the basal ganglia
The direct pathway: allows motor movements to happen
The indirect pathway: prevents a motor movement from happening
131
Each basal ganglia contains different classes of dopamine (DA) receptors with inverse effects. What are they?
The direct pathway: the D1-excitatory
The indirect pathway: the D2-inhibitory
132
When DA is released in the basal ganglia, how does it affect the rectors differently? Why?
The D1 (direct) = excited
The D2 (indirect) = inhibited
Causes body to perform a motor movement due to the receptor types found in networks of that brain area
Cell responses are dependent on the receptor types found, not the NT type
133
True or false: cell responses are dependent on the NT type, not the receptor types
False
Cell responses dependent on the receptor types
134
How can neurons be classified
Excitatory
Inhibitory
Characterized by the effect on the postsynaptic cells based
135
What are excitatory neurons
Neurons that cause the postsynaptic cells to depolarize
Increases AP likelihood
Typically forms synapses with the dendrites of the postsynaptic cell
136
What do most excitatory neurons release
Glutamate (Glu) = most common NT in the brain
137
What does Glutamate (Glu) bind to?
Typically bonds to glutamatergic receptors
138
What is an example of a Glu binding to a glutamatergic receptor?
AMPA receptors (an ionotropic Na+ receptor)
Glu binds, allowing Na+ to rush into cell
Depolarizes the membrane
139
What are inhibitory neurons?
Neurons that cause the postsynaptic cells to hyperpolarize
Decreases AP likelihood
Typically forms synapses with the cell body of the postsynaptic cell
140
What do most inhibitory neurons release
GABA = second most common NT in the brain
141
What does GABA bind to?
Typically binds to GABAergic receptors
142
What is an example of GABA binding to a GABAergic receptor
GABAa receptors (an ionotropic Cl- receptor)
GABA binds, allowing Cl- to rush into cell
Hyperpolarizing the membrane
143
True or false: cells that produce Glu and GABA have centralized locations
False
All across brain
144
What do excitatory and inhibitory neurons have in common when it comes to receptors
Both primarily interact with ionotropic receptors to either excite or inhibit other receptors
145
True or false: neuromodulator NTs have more widespread influence of activity than the local signaling of Glu and GABA
True
146
What are the four major NTs
Acetylcholine (ACh)
Dopamine (DA)
Norepinephrine (NE)
Serotonin (5-HT)
147
True or false: NT receptors are not consistently excitatory or inhibitory
True
148
How does modulation of NT work in synaptic transmission
Activity of other neurons modulate
Primarily interact with GPCR, resulting in longer term cellular processes when compared to Glu and GABA
149
What does production of NT work in synaptic transmission
Less prevalent than Glu and GABA
Each neuromodulator NT is produced in a centralized location where the cell body is located
Axons extend far distances to communicate with certain strcutures
150
Use DA to provide an example of production
DA produced in the midbrain
Axons extend to multiple targets (ex: basal ganglia, pituitary, cortex)
NTs are transported along axons to reach synaptic terminals and released in those locations
151
Drug and toxins are introduced into the ____ and interact with the brain and body. _____ transports the substance around the whole body
The bloodstream
152
What is the primary cause of side effects?
Body reuses the same chemical in different ways
Ligand binds to receptors
153
A substance’s effect is dependent on
Dose
Route of administration
154
True or false: a slight difference to the structure greatly influences how effective each opioid is at pain suppression
True
155
The most direct path from administration to the target tissue will have the most significant effect. Why?
The least amount of time to be broken down
156
Rank the routes of administration from slowest to fastest
Ingestion
Absorption (inside nose/mouth)
Intramuscular injunction (ex: flu shots)
Inhalation (ex: smoking)
Intravenous injection
157
What is the structure of the blood brain barrier
Astrocytes tightly wrap around blood vesicles in the brain
158
The blood-brain barrier allows in good and blocks bad so how can drugs still affect it?
small and uncharged substances can slip through
Drugs and toxins that interact with the brain pass through the BBB
159
What is an example of a medication that is meant to pass through the BBB?
Benadryl/diphenhydramine
Antihistamine = an antagonist = blocks muscus production
But also results in drowsiness and exhaustion because histamine keeps us awake
160
Althoguh Claritin provides allergy relief it doesn’t result in drowsiness. Why?
It has a different structure so it doesn’t pass through the BBB
Different molecular structure, larger and slightly uncharged
161
What is the neuromuscular junction?
location of communication from the nervous system to the muscles
162
Describe the presynaptic and postsynaptic parts of the neuromuscular junction
Presynaptic: axon, functions are identical to neuron-to-neuron synapses, releases acetylcholine (ACh)
Postsynaptic: muscle fiber, contracts when ACh binds to ACh receptors
163
How does Botox work
Breaks down the SNARE complex = prevents SNARE from operating
PNS axon is unable to release NT without SNARE complexes
Muscle fiver will not receive NTs when the axon is stimulated
Muscle fiber is permanently paralyzed
164
What would happen with a high dose of botox
Would enter the loop stream and circulate to neuromuscular junctions across the whole body
= possible death, generalized weakness
165
What is Botox used for
Cosmetics
tension headache treatment
Treating lazy eyes
166
Does Botox pass the BBB?
No, only acts on synapses in the PNS
167
What is an example of a medication that influences synaptic transmission by modulating the activity of NT reuptake proteins
SSRI (selective serotonin reuptake inhibitors)
Takes longer to clear all 5-HT out, increases amount of time its in the synaptic cleft, giving 5-HT more time to bind and unbind form receptors
168
SSRIs and cocaine have very different behavioral effects even though they have near identical mechanisms of action on the synapse. Why?
Influence signaling of different NTs = modulates different NT signaling in the brain will affect different receptors = diff effects
Cocaine affects DA
169
Which medication has the same activity component as cocaine?
Ritalin (used to treat ADHD)
170
Opioids are ____ for opioid receptors
Agonists
171
How does opioids affect pain receptors?
Endogenous (naturally made) opioids activate pain suppression receptors
Opioid drugs bind to receptors -> never perceive pain
172
True or false: endogenous opioids are released in big quantities
False
173
What is the danger of opioid drugs in the brain?
opioids Drugs will interact with all receptors in the brain + body
Drug concentration significantly higher than naturally released endogenous opioids
Oversaturate synapses ->
- changes behavior and perception of pain, euphoria, reward seeking behaviors
174
What are the long term effects of opioids biologically
The synapse will want to return to normal activation levels
Neurons will detect the over activation of opioid receptors
Opioids receptors are removed from the membrane
= weakened response to the same amount of ligand
175
True or false: opioid drugs bind intake will influence the response to future opioid drugs and endogenous opioids due to tolerance
True
176
Where is the reward pathway
Axons from the VTA to the nucleus accumbens (NA) and the cortex
177
A study with mice showed what about dopamine (DA)
Unexpectedly receive an award showed the same spike in VTA cells/DA as the cue for an upcoming reward and receive it but no increase of dopamine when receiving an award
= DA is not about happiness, rather “wanting”, reward anticipation
178
True or false: endogenous opioids will enhance the activity of DA axons
True
Opioids will oversaturate opioid receptors on interneurons, greatly inhibiting interneurons, greatly enhancing DA
179
What are the long term effects of opioids psychologically
NA will encode opioid stimuli as an extremely rewarding experience, increasing motivation to repeat opioids
Behaviors will prioritize experiencing more opioid stimuli over non-opioid stimuli
Non-opioid stimuli (food, sex, achieving goals, etc) will be less rewarding: same endogenous opioids but less receptors
180
What is opioids effect on respiration
Activation of opioids receptors will suppress breathing
Deaths due to overdose are typically due to asphyxiation
181
What common medication is an opioid receptor antagonist, allowing counteraction of opioids’ immediate effects
Naloxone
But can’t undo neurological changes
