文档介绍：Chapter 7 Cholinoceptor agonists
Pharmacology
Instructor : Lei Linsheng 雷林生
Cholinoceptor agonists are a large group of drugs that mimic acetylcholine and classified pharmacologically by their spectrum of action depending on the type of receptor that is activated.
Classification
1. M Cholinoceptor agonists
1) Choline esters
methacholine
carbachol
bethanechol
2) Alkaloids
pilocarpine
2. N Cholinoceptor agonists
nicotine
Acetylcholine
A. Muscarinic effect (M-effect)
iv small dosage
decreases heart rate and contractility
dilation of blood vessels, decline of blood pressure
constriction of bronchial muscle,
gastrointestinal, urinary tract,
uterus smooth muscle and pupil
SLUD response
--- Salivation
--- Lacrimation
--- Urination
--- Defecation
increases the secretion of gland (sweat, salivary, lacrimal, nasopharyngeal)
B. Nicotinic effects (N-effect)
Larger dosage
activates N1
-- produces and activates all the autonomic ganglia
-- resembles simultaneous discharge of both the parasympathetic and sympathetic nervous systems
activates N1 receptor of pheochrome cells of adrenal medulla--- releases adr.
activates N2, constriction of skeletal muscle
C. Therapeutic use
None---action is too transient
Not effective orally
Duration after IV-2 minutes
Methacholine 醋甲胆碱
Selective for M receptor
not easily hydrolyzed
by cholinesterase---
effects are longer
used to treat xerostomia
Measurement of bronchial hyperactivity (hyperresponsiveness)
(methacholine challenge激发test)
The methacholine challenge test is one method of assessing airway responsiveness. In this test, the patient inhales an aerosol of one or more concentrations of methacholine. Results of pulmonary function tests (eg, spirometry, specific conductance) performed before and after the inhalations are used to quantitate response. This guideline applies to adults and children capable of adequately performing spirometry or body plethysmography and of cooperating during th