二、接受器、次級訊息傳導物
receptor
|
G protein
|
signaling pathway
|
α1, D1, M1,3,5
|
Gq
|
↑phospholipase C→IP3, DAG, Ca2+
|
α2, D2, M2,4
|
Gi
|
↓adenylyl cyclase→↓cAMP
|
β
|
Gs
|
↑adenylyl cyclase→↑cAMP
|
三、接受器、生理作用
sympathetic activity
|
organ
|
parasympathetic activity
| ||
receptor
|
action
|
action
|
receptor
| |
Eye
| ||||
α1
|
contracts
|
iris radical muscle
|
─
|
─
|
─
|
─
|
iris circular muscle
|
contracts
|
M3
|
β
|
relaxes
|
ciliary muscle
|
contracts
|
M3
|
Heart
| ||||
β1, β2
|
accelerates
|
sinoatrial node
|
decelerates
|
M2
|
β1, β2
|
accelerates
|
ectopic pacemaker
|
─
|
─
|
β1, β2
|
increases
|
contractility
|
decreases
|
M2
|
Blood vessels
| ||||
α
|
contracts
|
skin, splanchnic vessels
|
─
|
─
|
β2, M3
|
relaxes
|
skeletal muscle vessels
|
─
|
─
|
─
|
─
|
endothelium of vessels in heart, brain, viscera
|
synthesis and releases EDRF
|
M3, M5
|
β2
|
relaxes
|
Bronchiolar smooth muscle
|
contracts
|
M3
|
GI tract
| ||||
smooth muscle
| ||||
α2, β2
|
relaxes
|
walls
|
contracts
|
M3
|
α1
|
contracts
|
sphincters
|
relaxes
|
M3
|
─
|
─
|
secretion
|
increases
|
M3
|
Genitourinary smooth muscle
| ||||
β2
|
relaxes
|
bladder wall
|
contracts
|
M3
|
α1
|
contracts
|
sphincters
|
relaxes
|
M3
|
β2
|
relaxes
|
uterus
|
─
| |
α1
|
contracts
| |||
α
|
ejaculation
|
penis
|
erection
|
M
|
Skin
| ||||
α
|
contracts
|
pilomotor smooth muscle
|
─
|
─
|
sweat gland
| ||||
M
|
increases
|
eccrine
|
─
|
─
|
α
|
increases
|
apocrine (stress)
|
─
|
─
|
Metabolic function
| ||||
β2, α
|
glucogenesis
|
liver
|
─
|
─
|
β2, α
|
glycolysis
| |||
β2
|
lipolysis
|
fat cells
|
─
|
─
|
β2
|
renin release
|
juxtaglomerular apparatus
|
─
|
─
|
