G-protein-linked 2nd messengers Flashcards
alpha-1
Gq: increases [Ca2+]
Increases: vascular smooth muscle contraction, pupillary dilatory muscle contraction (mydriasis), intestinal and bladder sphincter muscle contraction
alpha-2
Gi: decrease cAMP
Decreases: sympathetic outflow, insulin release, lipolysis,
Increases: platelet aggregation
beta-1
Gs: increases cAMP
Increases: HR, contractility, renin rlease, lipolysis
beta-2
Gs: increase cAMP
Vasodilation, bronchodilation, ciliary muscle relaxation
Increases: HR, contractility, lipolysis, insulin release, aqueious humor production
Decreases: uterine tone (tocolysis)
M1
Gq: increases [Ca2+]
CNS, ENS, GI secretions
M2
Gi: decrease cAMP
SA node: decrease HR (negative chronotropy)
AV node: decrease conduction velocity (negative dromotropy) and ventricular contraction
M3
Gq: increases [Ca2+]
Increases: exocrine gland secretions (lacrimal, salivary, gastric acid), gut peristalsis, bladder contraction, bronchoconstriction, pupillary sphincter muscle contraction (miosis), ciliary muscle contraction (accommodation)
D1
Gs: increase cAMP
Relaxes renal vascular smooth muscle
D2
Gi: decrease cAMP
Modulates transmitter release, especially in brain
H1
Gq: increases [Ca2+]
Increases: nasal and bronchial mucus production, vascular permeability, contraction of bronchioles, pruritus, and pain
H2
Gs: increase cAMP
Increases: gastric acid secretion
V1
Gq: increases [Ca2+]
Increases: vascular smooth muscle contraction
V2
Gs: increase cAMP
Increases: H2O permeability and reabsorption in collecting tubules of kidney