Neurotest1, Ch.3

Front 1

definition of a synapse

Back 1

a site at which neurons make a functional contact; a point of communication btwn a neuron and another cell

Front 2

most drugs that affect the CNS act at the ____

Back 2

synapse

Front 3

synapses can be ____ or ____

Back 3

electrical or chemical

Front 4

_____ synaptic transmission dominates in the CNS

Back 4

chemical

Front 5

the post-synaptic cell can be what three things?

Back 5

1. another neuron
2. muscle cell
3. gland

Front 6

synaptic contact between neurons can occur in what 3 places?

Back 6

1. axo-somatic synapse - axon synapse on cell body

2. axo-dendritic synapse - axon synapse on dendrite

3. axo-axonic synapse - axon connecting to another axon

Front 7

hippocampus

Back 7

learning and memory

Front 8

end plate potential (EPP) is where?

Back 8

at the neuromuscular junction

Front 9

neurotransmitter

Back 9

a chemical substance released from the presynaptic terminal causing an effect on the postsynaptic cell

can be fast acting or slow acting

Ach
Amino acids: glutamate, GABA, glycine
Peptides: substance P
Amines: dopamine, NE, serotonin

Front 10

neuromodulator

Back 10

a chemical substance that alters (modulates) the activity of many neurons.

acts at a distance from the synaptic cleft

ex: amines (dopamine, NE, serotonin)

Front 11

receptor

Back 11

a protein

typically named for the NT to which they bind.

Front 12

neurotransmitter receptors respond to the binding of a _____

Back 12

ligand

Front 13

NT receptors can be present on the postsynaptic membrane.

Can they be present on the presynaptic membrane?

Back 13

yes! NT receptors can be present on the presynaptic membrane.

Front 14

Describe the sequence of events at a neuron to neuron chemical synapse

Back 14

1. AP arrives at the presynaptic terminal
2. Electrotonic (passive) spread of excitatory current
3. Activation of voltage-gated Ca++ channels
4. Ca++ in the presynaptic terminal causes synaptic vesicles to fuse w/ the presynaptic membrane
5. NT is released (Quanta) and diffuses across the synaptic cleft
6. NT binds to postsynaptic receptor and alters postsynaptic cell function

Front 15

what are 3 ways that a synaptic event can be terminated?

Back 15

1. diffusion (NT diffuse away from synaptic cleft)
2. reuptake (carrier-mediated transport)
3. enzymatic degradation

Front 16

presynaptic effects occur when the amount of NT released by a neuron is influenced by previous activity in an ______ synapse

Back 16

axoaxonic synapse

pre-synaptic inhibition
pre-synaptic facilitation

Front 17

pre-synaptic inhibition

Back 17

an axon releases NT that slightly hyperpolarizes (IPSP) the axonal region of a 2nd axon.

the 2nd axon releases less NT

Front 18

glutamate is an ____ NT

Back 18

excitatory, causing an EPSP

Front 19

pre-synaptic facilitation

Back 19

axon releases NT that slightly depolarizes (EPSP) the axon terminal of a 2nd axon

Front 20

the amount of NT released from the presynaptic terminal is directly proportional to the ___ of AP arriving at the terminal

Back 20

frequency

Front 21

NT receptors can be ionotropic or metabotropic

what is ionotropic receptors?

Back 21

binding of the NT to the receptor causes a conformational change in the protein that opens an ion channel. 1st messenger; short acting; fast acting

ionotropic receptors are also known as ligand-gated channels

Front 22

what 3 NT's act on ionotropic receptors?

Back 22

1. glutamate (excitatory)
2. GABA (inhibitory)
3. glycine (inhibitory)

Front 23

what are metabotropic receptors?

Back 23

receptors that produce an intracellular 2nd messenger. the 2nd messenger then influences the activity of ion channels

long lasting, slow, G-protein mediated

Front 24

examples of metabotropic NT include

Back 24

1. serotonin
2. dopamine

Front 25

the NT for an AMPA (ionotropic) receptor is ___

Back 25

glutamate

Front 26

tell me about glutamate receptors

Back 26

always cation(positive) channels
can be ionotropic (ligand-gated, the receptor is also the channel, fast acting) or metabotropic (2nd messenger)
excitatory

AMPA: fast
NMDA: slower
Kainate: fast

Front 27

AMPA, NMDA, and Kainate are all examples of what type of receptors?

Back 27

glutamate receptors

excitatory

Front 28

tell me about GABA and Glycine receptors

Back 28

anion(negative) channels
inhibitory
can be ionotropic (ligand-gated) or metabotropic (2nd messenger)
Cl- comes in

Front 29

NT that act on metabotropic receptors and thus modulate the postsynaptic response are also called ______

what are some examples?

Back 29

neuromodulators

ex: neurotrophins, serotonin, amines(dopamine, NE) epi, glutamate, GABA

Front 30

the function of existing ionotropic receptors can be modulated by activation of ______ receptors

Back 30

metabotropic receptors (2nd messenger, example is serotonin)

this mechanism probably contributes to some forms of learning and memory

Front 31

the NT in the neuromuscular junction is always _____

Back 31

acetylcholine (ACh)

Front 32

ACh is degraded by what?

ACh is always _____

the postsynaptic event is known as the ____

there is no evidence for pre-synaptic inhibition

Back 32

acetylcholinesterase

always depolarizing (excitatory)

End Plate Potential

diseases involving neuromuscular junction: MG, curare, botulinum toxin