Autonomic receptor stimulation

sympathetic synapses

• adrenergic receptors

• preganglionic neuron → ganglionic transmitter (like ACh) → postganglionic neuron → neuroeffector transmitter releases into blood (norepi or epi) → effector organs (sympathetic response by organs)

adrenergic receptors

• located on cells of tissues and organs throughout the body, and are targets of catecholamines such as epinephrine and norepinephrine

• a1

• a2

• b1

• b2

a1

• location: smooth muscle, vascular walls, heart

• action: vasoconstriction

a2

• location: CNS, arterioles, pancreas

• action: sedation, analgesia, vasodilation, inhibition of insulin release

b1

• location: cardiac muscle, sinus node, AV junction

• action: increased HR and force of contractility

• TIP

  • ONE heart

    • increased HR & CO/CI

  • “cardioselective” - only b1 action

b2

• location: skeletal vascular, bronchial smooth muscle, liver, cell membranes

• action: vasodilation, bronchodilation, hepatic glycogenolysis

• TIP

  • TWO lungs

    • bronchodilation

  • 
    

dopamine (receptor)

• location: kidneys, heart, splanchnic organs, cerebral vascular beds

• action: vasodilation (at increased doses causes vasoconstriction)

vasopressin (receptor)

• location: vascular smooth muscle

• action: vasoconstriction