1. Adrenergic antagonists
Chapter 11
Adrenergic antagonists
肾上腺素受体拮抗剂剂

2. Subtypes and effects of adrenergic receptors
Presynaptic membrane
α2 receptor inhibiting the release of NA
β receptor promoting the release of NA
α 1受体
Promoting the contracting of the vascular smooth muscle in skin, mucosa, and kidney
β受体
β1 receptor excitation of the heart
β2受体
Relaxing the smooth muscle of bronchus
Relaxing the smooth muscle of coronary artery, and blood vessels in skeletal muscle
Negative feedback
Positive feedback
Pupil dilation
 Postsynaptic membrane

3. α-receptor antagonists
Phentolamine [fen'tɔləmi:n]
酚妥拉明
Effects
1 Decreasing blood pressure based on vasodilation effect;
2 Cardiac stimulation based on depressor reflex减压反射:
heart contractility ↑, heart rate ↑, cardiac output↑

5. 3 Cholinergic effects:
Increasing glandular secretion; promoting the contracting of smooth muscle.
4 Histamine like effects:
Increasing gastric acid secretion; lead to skin flush

6. Uses:
1 Peripheral vascular diseases: Raynaud’s syndrome 雷诺氏综合征, thromboangiitis [,θrɔmbəu,ændʒi'aitis]血栓血管炎;
2 Local vasoconstrictor血管收缩剂 excess;
3 Shock；
4 Pheochromocytoma [fi:əkrəuməsai'təumə]嗜铬细胞瘤;
5 Congestive heart failure.

7. Adverse effects
1 Postural hypotension (体位性低血压);
2 Tachycardia;
3 Nasal /'neizəl/鼻的 congestion (鼻粘膜充血) ;
4 Gastrointestinal stimulation.

8. Prazosin /'preizəusin/哌唑嗪
Effects: Block 1 receptor
Uses: Hypertension
Side effects:
Postural hypotension, tachycardia, nasal congestion, drowsiness

9. -adrenoceptor blocking drugs (-adrenoceptor antagonists)
1 2 receptor blockade effects
(1) Heart: 1 blockade→HR↓, heart conductivity↓, contractility↓, CO↓;
(2) 2 blockade→ vasoconstriction↑;
(3) 2 blockade→ bronchoconstriction [,brɔŋkəukən'strikʃən]支气管狭窄;
(4) Renin secretion↓

10. 2 Intrinsic sympathomimetic /,simpəθəumi'metik/拟交感的 activity;
3 Membrane stabilizing activity

11. Uses: 1 Cardiac arrhythmias;
2 Angina [æn‘dʒaɪnə] pectoris [’pektəris] 心绞痛
3 Hypertension
4 Hyperthyroidism [,haipə'θairɔidizəm]甲亢

12. Adverse effects Contraindication:
1 Induction or exacerbation [ek,sæsə‘beɪʃən] 恶化of asthma;
2 Inhibition of cardiac function;
3 Withdraw syndrome.
Contraindication:
Asthma
Serious heart failure

13. Typical drugs Propranolol [prəu'prænə,lɔl]普萘诺尔；
Metoprolol [mɪ'tɔprəlɔl] 美托洛尔

14. 大纲要求 Objective and requirements
Understand the blocking effects on α and β receptor, and the classification, characteristics, and pharmacological actions of α and β receptor antagonists.
Teaching contents
Pharmacological effects, mechanism of action, clinical uses of α adrenoreceptor antagonist phentolamine.
General description of the pharmacological effects, mechanism of action, clinical use of β adrenoreceptor antagonist propranolol.

15. Essential vocabulary
Adrenergic antagonists Depressor reflex Postural hypotension