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腦科學概論講義 2
Synaptic Transmission
(指定看書 第五版Ch 10)
楊靜修 老師
(內容含 Principle of Neuroscience Ch 8-Ch 10)
Synaptic Transmission
Electrical synapse and chemical synapse
• Electrical synapse (gap junction)
• Chemical synapse
Neuromuscular junction (NMJ)- end plate potential (EPP)
Central nervous system- excitatory postsynaptic potential
(EPSP)
- inhibitory postsynaptic potential
(IPSP)
想想electrical 與 chemical synapse兩者差異在那裡？
重要
Electrical Synapse
Electrical synapse
Electrical synapse
Electrical synapse: gap junction
Electrical synapse: gap junction
Chemical Synapse
Chemical synapse:
Chemical synapse:
Vg Ca2+ channel
Ca2+
2o-active transport
counter transport
Chemical synapse:
許多電生理及分子機轉下節課範圍
Chemical synapse:
本節課範圍
下節課範圍
Chemical synapse:
neuromuscular junction
(第五版Ch 9)
Chemical synapse: neuromuscular junction
1.very accessible to experimentation
2.one muscle one neurotransmitter
3.one presynaptic axon
4.simple mechanism
5.single type of ion channel
Chemical synapse: neuromuscular junction
Nicotinic receptor: radiolabeled a-bungarotoxin
Nicotinic receptor
重要
Nicotinic receptor
Nicotinic receptor
Nicotinic receptor
gate
filter
Electrophysiological properties:
end-plate potential (EPP) in muscle cell
Curare (箭毒）: ACh receptor antagonist
EPP: (local response) in muscle cell
Patch clamp: single channel recording
Patch clamp: nicotinic receptor
V=IR I/V=1/R
IV-curve: slope=1/R (conductance)
Summary: neuromusclar junction
EPP
AP
Summary: neuromusclar junction
重要
Vg Ca2+ channel
Nicotinic receptor
Na+
N receptor
K+
depolarization
Vg Na+ Channel--AP
Vg K+
重要
Miniature endplate potentials
(MEPPs)
1. Spontaneous and random timesone vesicle ACh release (a quantum)
2. In muscle cell (mechanism類似EPP
但很小約0.4 mV) (EPP約15-20 mV)
合成之酵素
choline-O-acetyltransferase
Chemical synapse:
Central nervous system
(第五版Ch 10)
COMMUNICATION:
Presynaptic membranes
“deliver information”
in the form of
neurotransmitters.
Postsynaptic
membranes
“receive information”
because they have
receptors
for neurotransmitters.
Central Nervous System
Four primary neurons
communicate to one
secondary neuron.
One primary neuron
communicates to four
secondary neurons.
IPSP and EPSP
重要
EPSP: glutamate receptor
IPSP: Cl- channel
CNS-synaptic transmission
Sti 1
Sti 2
Recording 1
EPSP: glutamate receptor EPSP
IPSP: Cl- channel
Recording 2
IPSP
EPSP: glutamate receptor
(AMPA, kainate)
EPSP: glutamate receptor
下節課範圍
EPSP: glutamate receptor
IPSP: Cl- channel
Chemical synapse: many to one
重要
下圖說明為何是在 trigger zone
決定產生動作電位
B cell較近trigger zone
影響力較大
重要
1. Spatial summation (空間總合)
2. Temporal summation (時間總合)
下節課範圍
下節課範圍
由receptor決定反應為何
下節課範圍
CNS-synaptic transmission
excitatory and inhibitory
excitatory
inhibitory
下節課範圍
Axo-axonal communication (here, between A & B)
can modify classical synaptic communication
(here, between B & C); this can result in
presynaptic inhibition or presynaptic facilitation.
Note: the Terminal B must have receptors
for the signal released from A.
下節課範圍
Synaptic Transmission
Electrical synapse and chemical synapse
• Electrical synapse (gap junction)
• Chemical synapse
Neuromuscular junction (NMJ)- end plate potential (EPP)
Central nervous system- excitatory postsynaptic potential
(EPSP)
- inhibitory postsynaptic potential
(IPSP)
Chemical synapse: many to one