section name header

Table 15-2

ReceptorPotencyAgonistsAntagonistsLocationAction
α1++++
+++
++
+		Norepinephrine
Epinephrine
Dopamine
Isoproterenol		Phenoxybenzamine*
Phentolamine*
Ergot alkaloids*
Prazosin		Smooth muscle (vascular, iris, radial, pilomotor, uterus, trigone, GI and bladder sphincters)Contraction
Vasoconstriction
Tolazoline*
Labetalol*		Brain
Smooth muscle (GI)
Heart		Neurotransmission
Relaxation
Glycogenolysis
α2++++ClonidineYohimbineAdrenergic nerve endingsInhibition of norepinephrine release
+++NorepinephrinePiperoxan
++EpinephrinePhentolamine* Presynaptic (CNS)Aggregation
++NorepinephrinePhenoxybenzamine* Granule release
+PhenylephrineTolazoline* Platelets
Labetalol* Inhibition of lipolysis
Adipose tissueInhibition of insulin release
Inhibition of renin release
Endocrine pancreasNeurotransmission
Kidney
Brain
β1++++Isoproterenol* AcebutololHeartIncreased heart rate
Increased contractility
Increased conduction velocity
+++EpinephrinePractolol
++NorepinephrinePropranolol*Coronary vasodilation
+DopamineAlprenolol* Adipose tissueLipolysis
Metoprolol
Esmolol
β2++++IsoproterenolPropranolol* LiverGlycogenolysis
Gluconeogenesis
+++EpinephrineButoxamine
NorepinephrineAlprenolol
+DopamineEsmololSkeletal muscleGlycogenolysis
Lactate release
Nadolol
TimololRelaxation
LabetalolSmooth muscle
Dopamine1 ++++FenoldopamVascular smooth muscleVasodilation
++DopamineHaloperidolRenal
+EpinephrineDroperidolMesentery
MetoclopramidePhenothiazines
Dopamine2 ++DopamineDomperidonePresynaptic-adrenergic nerve endingsInhibition of norepinephrine release
+Bromocriptine

*Nonselective.

CNS = central nervous system; GI = gastrointestinal.