Adrenergic Drugs Flashcards
a1 type
G protein
Effect
Gq
Inc. IP3, DAG
a2 type
G protein
Effect
Gi
Dec. cAMP
b type
G protein
Effect
Gs
Inc. cAMP
Which D receptors are Gs?
D1 and D5
Inc. cAMP
Which D receptors are Gi?
D2, D3, D4
Dec. cAMP
a1 actions at:
Vascular SM
Pupillary dilator m.
Prostate
Heart
Vascular SM - contraction
Pupillary dilator m. - contraction (pupillary dilation)
Prostate - contraction
Heart - inc. force of contraction
a1 receptors are at which tissues? (4)
Vascular SM
Pupillary dilator m.
Prostate
Heart
a2 actions at:
Platelets
Adrenergic/cholinergic nerve terminals
Some vascular SM
Adipocytes
Platelets - aggregation
Adrenergic/cholinergic nerve terminals - inhibit transmitter release
Some vascular SM - contraction
Adipocytes - inhibit lipolysis
a2 receptors are at which tissues? (4)
Platelets
Adrenergic/cholinergic nerve terminals
Some vascular SM
Adipocytes
b1 actions at:
Heart
JG cells
Heart - inc. rate AND force of contraction
JG cells - inc. renin release
b1 receptors are at which tissues? (2)
Heart
JG cells
b2 actions at:
Respiratory, uterine and vascular SM
Skeletal m.
Liver
Respiratory, uterine and vascular SM: SM relaxation
Skeletal m.: inc. K+ uptake
Liver: activate glycogenolysis and gluconeogenesis
b2 receptors are at which tissues? (3)
Respiratory, uterine and vascular SM
Skeletal m.
Liver
D1 actions at:
SM
SM - dilates renal BVs
D2 actions at:
Nerve endings
Modulate NT release
How do indirect-acting adrenergic drugs produce an effect?
By increased/decreasing conc. of NE at target receptors.
Indirect-acting drugs and their manner of action (3)
- Cocaine: reuptake blockers of DA and NE.
- Phenelzine, selegiline: MAO inhibitors.
- Amphetamines and Ephedrine: releasing agents and direct receptor agonist.
Receptors for phenylephrine
a1>a2
Receptors for clonidine
a2>a1
Receptors for NE
a1=a2; b1>b2
Receptors for Epi
a1=a2; b1=b2
Receptors for Dobutamine
b1>b2 and a1
Receptors for Isoproterenol
b1=b2
Receptors for Albuterol
b2>b1