TABLE 1.

Effects of stimulation of adrenoceptor subtypes—adapted from Westfall and Westfall ¹⁴

	α1	α2	β1	β2
Localization	Brain Eye Gut vascular beds Lung Bladder	Brain (presynaptic) Spinal cord Synapses upon peripheral organ systems	Heart Brain	Heart Smooth muscle Lung Vasculature Uterus Brain Striate muscle
Effects	• Stimulant effects • Pupillary dilation • Vasoconstriction • Bronchoconstriction • Increased blood pressure	• Sedation • Inhibition of norepinephrine, insulin and acetylcholine release • Decreased blood pressure	• Positive chronotropic effect • Positive ionotropic effect • Neuromodulation	• Cardiac stimulation • Decreased smooth muscle tone: aorta, bronchiole (increase oxygen utilization), uterus and bladder colon • Decreased pulmonary inflammation • Increased attention • Increased glucose uptake (muscle)
Pharmacology
Selective agonists	Phenylephrine	Clonidine	Xamoterol	Albuterol
Selective antagonists	Prazosin	Yohimbine	Bisoprolol	ICI‐118,551

Note: Potentially performance‐enhancing effects are in bold.