Page 20 - pharma 1 theoretical updated MNU_Neat

Clinical pharmacy 2024/2025 Level 3 Pharm D Pharmacology 1 (PO 502)

Adrenergic receptors are classified as alpha (α) and beta (β)

α-receptors β-receptors
(smooth muscle, blood vessels) )heart , kidney , blood vessels)

subdivided into subdivided into
1. α1 (post-synaptic) 1. β1 (Heart),
2. α2 (pre-synaptic)→ Auto 2. β2 (Lung , kidney, smooth muscle and
regulatory most other sites)

3. β3 in adipose tissues
 Nb

❖ α2 agonist →  NE release →  activity of α1
❖ α2 Antagonist →  NE release→ activity of α1

➢ Ahlquist & discovery of Receptor (1948) dead 1983

Epi NE Isoproterenol

Relaxation & Contraction Contraction of Smooth Relaxation of Smooth
of Smooth muscle muscle muscle

Act on 2 different receptors Act pure on receptor ➔ Act pure on receptor ➔
➔  & B called  called β

rank order by Ahlquist

On  NE > Epi >>>> Iso

On β Isoproterenol > E> NE

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