Autonomic Pharmacology Flashcards
steps of neurotransmission
- synthesis
- storage
- release
- action at receptor
- termination
what kind of receptor is a muscarinic cholinergic receptor
GPCR
how many types of muscarinic receptors are there?
5 subtypes, 2 subgroups
stimulatory muscarinic cholinergic receptors
M1, M3, M5
inhibitory muscarinic cholinergic receptors
M2, M4
endogenous ligand of muscarinic cholinergic receptor
ACh
autonomic effector tissues
heart, endothelium, smooth muscle, glands, and the CNS
M1
CNS
M2
heart
M3
smooth muscle, glands, endothelium, eye (circular and ciliary muscle)
M4
CNS
M5
CNS
nicotinic cholinergic receptor type
ligand-gated Na+ and K+ depolarizing channel
two subtypes of nicotinic receptor
NicN and NicM
location of nicotinic receptors
autonomic ganglia, skeletal muscle innervation, CNS
muscarinic cholinergic receptor transmission
ACh binds –> confirmational change –> g protein breaks off –> second messenger –> causes a cellular response
nicotinic cholinergic receptor transmission
ACh binds –> confirmational change –> channel opens and positively charged ions influx through channel
NicN
ANS ganglia (all), adrenal medulla, CNS
NicM
skeletal muscle NMJ
alpha adrenergic receptor type
GPCR
alpha adrenergic receptor ligand
NE; also EPI and Dopa in large doses
excitatory alpha adrenergic receptor
alpha1
alpha1 adrenergic receptor transmission
increase in calcium –> calmodulin activation –> increased actin/myosin interaction –> smooth muscle contraction
inhibitory alpha adrenergic receptor
alpha 2
alpha2 adrenergic receptor transmission
decrease in cAMP –> decrease in NE release
alpha1
excitatory; smooth muscle, GU sphincters (esp. bladder), most vascular smooth muscle (skin, splanchic), eye (radial muscle), heart, liver
alpha 2
inhibitory; pre-synaptic nerve terminal, platelets, pancreatic beta cells
beta adrenergic receptor type
GPCR
beta adrenergic receptor ligand
NE, Epi
beta adrenergic receptor transmission
activation of adenyl cyclase –> increase in cAMP –> increase in kinase activation and phosphorylation of protein
beta adrenergic receptor tissues
heart, kidney, liver, smooth muscle, skeletal muscle, fat cells
beta1
heart, kidney (JG cells - cause renin release)
beta2
smooth muscle (bronchiolar, uterine, etc.), vascular smooth muscle (skeletal muscle beds), liver, skeletal muscle, heart
beta3
adipose tissue
PSNS action
rest and digest
PSNS origin
cranial nerves (III, VII, IX, X) and sacral region vagus nerve 90%
PSNS ganglia location
target organ
PSNS preganglionic length and NT
long, ACh
PSNS postganglionic length and NT
short, ACh
divergence of PSNS
discrete; this is because postganglionic neurons are not branched, but are directed to a specific target organ
PSNS receptor on postganglionic neuron
cholinergic
SNS action
fight or flight
SNS origin
thoracolumbar region of spinal cord; T1-T12 and L1-L5
SNS ganglia location
sympathetic chain ganglion or paravertebral chain
SNS preganglionic length and NT
short, ACh
SNS postganglionic length and NT
long, NE
divergence of SNS
diffuse; because postganglionic neurons may innervate more than one organ
SNS receptor on postganglionic neuron
adrenergic
exceptions to dual innervation
- adrenal medulla (SNS)
- most sweat glands (SNS)
- kidney (SNS)
- blood vessels (SNS)
- piloerector muscle (SNS)
eye iris radial muscle
SNS - alpha1 - contracts (mydriasis)
eye iris circular muscle
PSNS - M3 - contracts (miosis)
eye ciliary muscle
SNS - beta2 - relaxes (far vision)
PSNS - M3 - contracts (near vision)
SA node
SNS - beta1 - accelerates (increased HR)
PSNS - M2 - decelerates (decreased HR)
ectopic pacemakers
SNS - beta1 - accelerates (increased HR)
contractility of myocardium
SNS - beta1 - increases (increased force of contraction)
PSNS - M2 - decreases (atria, decreased force of contraction)
skin, splanchnic blood veseels
SNS - alpha1 - contracts (vasoconstriction)
skeletal muscle blood vessels
SNS - beta2 - relaxes (vasodilation)
bronchiolar smooth muscle
SNS - beta2 - relaxes (bronchodilation)
PSNS - M3 - contracts (bronchoconstriction)
GI walls
SNS - alpha2, beta2 - relaxes
PSNS - M3 - contracts
GI sphincters
SNS - alpha1 - contracts
PSNS - M3 - relaxes
GI secretion
SNS - alpha2 - decreases
PSNS - M3 - increases
GU bladder wall
SNS - beta2 - relaxes
PSNS - M3 - contracts
GU Sphincter
SNS - alpha1 - contracts
PSNS - M3 - relaxes
Uterus (pregnant)
SNS - beta2 - relaxes
SNS - alpha1 - contracts
PSNS - M - contracts
Penis seminal vesicles
SNS - alpha1 - ejaculation
PSNS - M - erection
pilomotor smooth muscles
SNS - alpha1 - contracts
sweat glands eccrine
SNS - M - increases