Lecture 9: Pharmacology of peripheral nervous system Flashcards
Neurotransmitters of ANS
- Preganglionic neurons: Acetylcholine
- Parasympathetic postganglionic neurons: Acetylcholine
- Sympathetic postganglionic neurons: Norepinephrine
2 types of cholinergic receptors
- Nicotinic receptors (LGIC) - leads to depolarization
2. Muscarinic receptors (GPCR) - depends on G-protein signalling cascade
2 types of adrenergic receptors
- Alpha (GPCR)- most common
2. Beta (GPCR) - all activates cAMP, different affinities for NE and epinephrine
Signal transduction of Alpha 1 Adrenergic receptors
Gq, PLC, Calcium release
depolarization
Phenylephrine (selective agonist)
Prazosin (selective antagonist)
Signal transduction of Alpha 2 adrenergic receptor
Gi, inhibit adenylyl cyclase, decrease cAMP
hyperpolarization
Clonidine (selective agonist)
Rauwolscine (selective antagonist)
Signal transduction at Beta adrenergic receptor
cAMP signalling via PKA
PKA phosphorylates metabolic enzymes, transcription factors and VGIC
B1 and B2 receptors and their affinity towards NE and EPI
B1: excitatory NE=EPI affinity
B2: inhibitory EPI»NE affinity
Locations of a1 receptors
vascular smooth muscles and pupils
Locations of a2 receptors
CNS, platelets, adipose tissue, some smooth muscle, nerve terminals
Locations of B1, B2 and B3 receptors
B1: CNS, cardiac muscles, kidney
B2: blood vessels, respiratory tract, uterus
B3: adipose tissue, gallbladder, bladder