Alpha & Beta adrenergic receptors

alpha 1

- smooth muscle contraction
- dilation of pupil(mydriasis)
- vasoconstriction
- agonist: NE, phenylephrine
- antagonist: phentolamine, TCA, H1-antagonist

  • contraction of vascular and genitourinary smooth muscle 

alpha 2

- negative feedback on NE -> 혈압을 감소시키는 역할


- inhibition of insulin release
- induction of glucagon release
- contraction of spincter in GIT

  • contraction of vascular smooth muscle
    decreased insulin secretion
    aggregation of platelet
    pre-synaptic inhibition of NE

beta 1

- inotropic effect
- agnoist: dobutamine
[* Increase cardiac output by increasing heart rate (positive chronotropic effect), conduction velocity (positive dromotropic effect), stroke volume (by enhancing contractility—positive inotropic effect), and rate of relaxation of the myocardium, by increasing calcium ion sequestration rate (positive lusitropic effect), which aids in increasing heart rate.]
- antagonist: metoprolol, atenolol
- located commonly in the heart and kidneys.

  • positive inotropic and chronotropic effects on the heart

beta 2

- smooth muscle relaxation
- agonist: salbutamol, salmeterol
- antagonist: timolol, propranolol
- located mainly in the lungs, gastrointestinal tract, liver, uterus, vascular smooth muscle, and skeletal muscle.

  • relaxes vasuclar, bronchial, GI, GU smooth muscle
    glycogenolysis and gluconeogenesis in the liver

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