Alpha and Beta Adrenergic Receptors : Mnemonics

Location

Alpha = Arteries and smooth muscles

Beta = Beats or Breaths

Types and Action

1 = Contract

2 = Dilate

Receptors

Alpha 1:

• Vasoconstriction
• Mydriasis (contraction of iris dilator muscles)
• Bladder sphincter contraction
• Uterus contraction

Alpha 2:

• Smooth muscle dilation
• Presynaptic terminal inhibition (negative feedback)

Beta 1:

Mnemonic: We have 1 HEART

• Increase heart rate and contraction

Beta 2:

Mnemonic: We have 2 LUNGS

• Dilate smooth muscles including bronchioles

Beta 3:

Mnemonic: 3 = Triglyceride

• Lipolysis