chapter 3: neurotransmission Flashcards
(153 cards)
1
Q
neurotransmission involving membranes coupled by gap junction channels and a direct flow of ions; can be either depolarized or hyperpolarized but both cells must be the same
A
electrical neurotransmission
2
Q
transmission of chemical information between neurons
A
chemical neurotransmission
3
Q
local difference between the electrical charge across the membrane (i.e. the difference in electric charge inside the cell vs. outside)q
A
electrical potential
4
Q
reduction in the electrical potential; charge becomes less negative on the inside; brings the neuron closer to its firing threshold
A
depolarization
5
Q
increase in the electrical potential; charge becomes more negative on the inside; moves the neuron further from its firing threshold
A
hyperpolarization
6
Q
the electrical potential when a neuron is not firing; remains relatively stable
A
resting potential
7
Q
what is the value of resting potential?
A
-70mV
8
Q
during resting potential, Na+ channels are __________, K+ channels are __________, and negatively charged proteins are trapped __________
A
closed, open, inside
9
Q
neuronal membrane mechanism that maintains resting potential
A
Na+/K+ pump
10
Q
pores in a neuronal membrane that allow the passage of ions
A
ion channels
11
Q
ion channels that open upon association with a specific molecule
A
ligand-gated
12
Q
ion channels that open when the membrane reaches a certain charge
A
voltage-gated
13
Q
ion channels that open when the membrane is stretched
A
mechanically-gated
14
Q
changes in membrane potential to dendrites in repsonse to neurotransmitters; can be excitatory or inhibitory
A
postsynaptic potentials
15
Q
the soma sums EPSPs and IPSPs to determine if potential is enough to trigger __________
A
an action potential
16
Q
increases membrane potential until it reaches the threshold for an action potential
A
EPSP
17
Q
why does K+ stay inside the cell despite being able to flow in and out to where K+ is less concentrated, and Na+ stays outside the cell?
A
charged molecules consider both gradients
18
Q
rapid depolarization of an axon as a result of the sum of inputs by the soma
A
action potential
19
Q
what is the value of the firing threshold for an action potential?
A
-55mV
20
Q
what does Na+ do when an action potential is triggered?
A
enters the cell
21
Q
why does Na+ enter the cell when an action potential is triggered?
A
concentration gradient
22
Q
what happens to the polarity of the inside of a cell when an action potential is triggered?
A
reverses locally
23
Q
by how much does the polarity of the inside of a cell change when an action potential is triggered?
A
+30mV
24
Q
what happens to Na+ during repolarization?
A
channels close
25
what does K+ do during repolarization?
exits the cell
26
why does K+ exit the cell during repolarization?
no more electrical gradient keeping it inside
27
time during which resting potential is being restored (via Na+/K+ pump)
refractory period
28
during resting potential, are Na+ and K+ in or out of the cell?
K+ in, Na+ out
29
a series of action potentials that travel down the axon
saltatory conduction
30
start of propagation of action potentials; where the axon connects to the soma
axon hillock
31
junctions between segments of myelin, source of charging during saltatory conduction
nodes of ranvier
32
what prevents the backflow of ions and makes saltatory conduction unidirectional?
refractory periods
33
what affects the firing rate of a neuron?
amount of stimulation by other neurons
34
main site of action for most psychoactive drugs
neurotransmitters
35
chemicals that synthesize neurotransmitters from precursor molecules
enzymes
36
store and protect NTs after synthesis
synaptic vesicles
37
package and transport NTs for storage after synthesis
vesicular transporters
38
release of neurotransmitters by vesicles fusing to the plasma membrane of the presynapse, releasing their contents
exocytosis
39
what ion enters the cell in response to an AP along with Na+?
Ca2+
40
another word for NTs
ligands
41
NT receptors change shape when NTs bind to them
conformational change
42
enzymatic breakdown of the NT
catabolism
43
conversion of a NT or other molecules to a metabolite
turnover
44
specialized proteins embedded in neuronal membranes to which NTs bind and activate
receptors
45
how many NTs can activate a certain receptor?
one
46
how many receptors can a NT bind to?
multiple
47
presynaptic receptor activated by NTs released from the same axon terminal
autoreceptor
48
presynaptic receptor activated by NTs different from those released from the axon terminal
heteroreceptor
49
receptor that is coupled to an ion channel
ionotropic
50
effects __________ when NT is no longer bound to an ionotropic receptor
end
51
receptor that is far from where its effects are seen
metabotropic
52
what happens when a NT binds to an ionotropic receptor?
ion channels open
53
when a NT binds to an ionotropic receptor, local membrane potential is either __________ or __________ depending on the ion
depolarized or hyperpolarized
54
what happens when a NT binds to a metabotropic receptor?
G protein activates
55
what activates intracellular signaling?
G protein
56
generates second messengers during intracellular signaling
effector enzymes
57
open/close ion channels elsewhere on the cell membrane; trigger pathways to activate transcription factors via kinases (enzymes)
second messengers
58
effects __________ when NT is no longer bound to a metabotropic receptor
persist
59
3 subunits of G proteins
alpha, beta, gamma
60
GABA and glutamate
amino acids
61
most abundant excitatory NT
glutamate
62
all glutamate receptors
NMDA, AMPA, kainate, mglu group i, mglu group ii, mglu group iii
63
which glutamate receptors are only expressed during fetal development?
inhibitory mglu
64
type and effect of NMDA (glutamate receptor)
ionotropic, excitatory
65
type and effect of AMPA (glutamate receptor)
ionotropic, excitatory
66
type and effect of kainate (glutamate receptor)
ionotropic, excitatory
67
type and effect of mglu group i
metabotropic, excitatory
68
type and effect of mglu groups ii and iii
metabotropic, inihibitory
69
what ion is allowed to pass through NMDA (glutamate receptor)?
Ca2+
70
what is NMDA (glutamate receptor) important for?
learning and memory
71
does AMPA (glutamate receptor) allow Ca2+?
no
72
enzyme that synthesizes glutamine from glutamate
glutamine synthetase
73
where does glutamine synthetase occur?
astrocyte
74
__________ reenters the pre-synapse and not __________ in order to avoid unnecessary excitatory responses
glutamine, glutamate
75
most abundant inhibitor
GABA
76
all GABA receptors
GABAa, GABAb
77
GABAa type and effect
ionotropic, inhibitory
78
GABAb type and effect
metabotropic, inhibitory
79
drug that increases availability of the enzyme glutamic acid decarboxylase to convert glutamate to GABA
gabapentin/neurontin
80
what types of drugs affect GABA receptors?
benzodiazepine, ethanol, barbiturates
81
what kind of drugs are benzodiazepines?
anti-anxiety
82
what kind of drug is ethanol?
alcohol
83
what kind of drugs are barbiturates?
painkillers
84
what type of glia is important in recycling GABA?
astrocytes
85
GABA transporter
GAT
86
structure shared by all catecholamines
catechol nucleus
87
two subcategories of monoamines
catecholamines, indolamines
88
what are catecholamines synthesized from?
tyrosine
89
what are indolamines synthesized from?
tryptophan
90
name the catecholamines
dopamine, epinephrine, norepinephrine
91
name the indolamines
serotonin, melatonin
92
chemical absorbed from high-protein food such as meat, soy, and dairy products
phenylalanine
93
enzyme that converts phenylalanine to tyrosine
phenylalanine hydroxylase
94
enzyme that converts tyrosine to L-DOPA
tyrosine hydroxylase
95
enzyme that converts L-DOPA to dopamine
aromatic L-amino acid decarboxylase
96
what is the rate-limiting step in the process of dopamine synthesis?
tyrosine hydroxylase
97
dopamine receptors are all __________
metabotropic
98
all dopamine receptors
D1, D2, D3, D4, D5
99
D1 family receptors and their effect
D1, D5, excitatory
100
D2 family receptors and their effect
D2, D3, D4, inhibitory
101
dopamine transporter
DAT
102
what are the important dopaminergic pathways?
mesolimbic, mesocortical, nigrostriatal, tuberoinfundubular
103
reward pathway from the ventral tegmental area (VTA) to the limbic system
mesolimbic
104
dopaminergic pathway from the ventral tegmental area (VTA) to the neocortex (including the pre-frontal cortex)
mesocortical
105
what is overactivation of the mesocortical pathway associated with?
schizophrenia
106
which dopaminergic pathway is the target of anti-psychotic drugs (blocks DA)?
mesocortical
107
dopaminergic pathway from the substantia nigra to the basal ganglia
nigrostriatal
108
dopaminergic pathway from the hypothalamus to the pituitary gland
tuberoinfundibular
109
hormone that regulates the production of milk
prolactin
110
what was DA originally called when it was first discovered?
prolactin inhibitory factor
111
enzyme that converts dopamine to norepinephrine
dopamine beta hydroxylase
112
all norepinephrine receptors
a1, a2, b1, b2, b3
113
norepinephrine receptors are all __________
metabotropic
114
all norepinephrine receptors besides a2 are __________
excitatory
115
norepinephrine receptor a2 is the only norepinephrine receptor that is __________
inhibitory
116
norepinephrine transporter
NET
117
enzyme that breaks down monoamines including dopamine, norepinephrine, and serotonin
MAO
118
enzyme that breaks down catecholamines such as dopamine and norepinephrine
COMT
119
forms an important noradrenergic pathway; projects to the cerebral cortex, amygdala, and hippocampus; important for arousal, attention, stress, and memory
locus coeruleus
120
what disease causes early damage to the locus coeruleus?
alzheimer's disease
121
abbreviated name for serotonin
5-HT
122
enzyme that synthesizes 5-hydroxytryptophan from tryptophan (from diet)
tryptophan hydroxylase
123
enzyme that synthesizes serotonin from 5-hydroxytryptophan
aromatic L-amino acid decarboxylase
124
where else is 5-HT synthesized besides the brain for the purpose of motility?
gut
125
all serotonin (5-HT) receptors
5-HT1, 5-HT2, 5-HT3, 5-HT4, 5-HT5, 5-HT6, 5-HT7
126
all serotonin receptors besides 5-HT3 are __________
metabotropic
127
what type of receptor is 5-HT3?
ionotropic
128
all 5-HT receptors besides 5-HT1 and 5-HT5 are __________
excitatory
129
what effect do receptors 5-HT1 and 5-HT5 have on a neuron?
inhibitory
130
what is the ONLY enzyme that breaks down serotonin after it is transported back to the pre-synapse?
MAO
131
serotonin transporter
SERT
132
forms an important serotonergic pathway; projects to the forebrain and spinal cord; regulates mood and influences food intake
raphe nuclei
133
is the production of amino acids glutamate and GABA localized or throughout the brain?
throughout
134
is the production of monoamines localized or throughout the brain?
localized
135
enzyme that synthesizes acetyl coenzyme A and choline into acetylcholine
choline transferase
136
where does acetyl coenzyme A come from?
metabolism
137
where does choline come from?
diet or metabolism
138
all acetylcholine receptors
muscarinic M1, muscarinic M2, muscarinic M3, muscarinic M4, muscarinic M5, nicotinic
139
all muscarinic ACH receptors are __________
metabotropic
140
what type of receptor is nicotinic (ACH receptor)?
ionotropic
141
all ACH receptors besides muscarinic M2 and muscarinic M4 are __________
excitatory
142
ACH receptors muscarinic M2 and M4 are __________
inhibitory
143
ACH acting through nicotinic receptors is the cause of __________
muscle contraction
144
aricept/donepezil is a drug that counteracts ACH depletion to treat what disease?
alzheimer's disease
145
forms an important cholinergic pathway; projects to the cerebral cortex; alzheimer's disease is characterized by degeneration of more than 2/3 of cholinergic neurons in this structure
nucleus basalis magnocellularis
146
what are two other important cholinergic pathways that are not part of the brain?
somatic nervous system, parasympathetic nervous system
147
what kind of NTs are endorphins and enkephalins (opioids)?
neuropeptides
148
hormone that regulates uterine contraction, milk, and emotional connections with others
oxytocin
149
hormone that regulates water/salt balance in the kidneys
vasopressin
150
family of molecules that promotes the survival and plasticity of neurons during development and in adulthood
neurotrophins
151
two important types of neurotrophins
nerve growth factor, brain-derived growth factor
152
metabotropic receptor subtype (enzyme) that does not have a G protein
tyrosine kinase receptor
153
do germ-free mice (no gut flora) exhibit a higher or lower stress response than non-germ-free mice?
higher
