Podcast
Questions and Answers
What are drugs that mimic acetylcholine (Ach) called?
What are drugs that mimic acetylcholine (Ach) called?
Cholinomimetics
Cholinomimetics are divided into what two categories?
Cholinomimetics are divided into what two categories?
What is the name for the type of cholinomimetic that directly stimulates Ach receptors?
What is the name for the type of cholinomimetic that directly stimulates Ach receptors?
Direct-acting cholinomimetics
What is the name for the type of cholinomimetic that inhibits cholinesterase?
What is the name for the type of cholinomimetic that inhibits cholinesterase?
Signup and view all the answers
What are the two main types of Ach receptors?
What are the two main types of Ach receptors?
Signup and view all the answers
Which are examples of direct-acting cholinomimetics?
Which are examples of direct-acting cholinomimetics?
Signup and view all the answers
Choline esters are relatively lipid soluble.
Choline esters are relatively lipid soluble.
Signup and view all the answers
Which of the following statements is TRUE about choline esters?
Which of the following statements is TRUE about choline esters?
Signup and view all the answers
Which of these choline esters has negligible effects on nicotinic receptors?
Which of these choline esters has negligible effects on nicotinic receptors?
Signup and view all the answers
What is the reason that Methacholine and Bethanechol have minimal effects on nicotinic receptors?
What is the reason that Methacholine and Bethanechol have minimal effects on nicotinic receptors?
Signup and view all the answers
What is the main action of Bethanechol?
What is the main action of Bethanechol?
Signup and view all the answers
Study Notes
Direct Acting Cholinergic Agonists (Cholinomimetics)
- Cholinergic agonists mimic acetylcholine (ACh) actions
- Divided into direct-acting and indirect-acting
- Direct-acting stimulate ACh receptors
- Indirect-acting inhibit acetylcholinesterase (AChE)
- They cause parasympathetic effects
Parasympathetic Division Effects
- Eye: Constricts pupil (miosis)
- Eye: Ciliary muscle contraction for near vision, increases aqueous outflow
- Eye: Reduces intraocular pressure
- Salivary Glands: Stimulates saliva production
- Lung: Constricts bronchi
- Heart: Inhibits heart rate
- Stomach, Pancreas, Intestines: Stimulates contractions/secretions (motility)
- Liver: Stimulates digestive secretions
- Bladder: Stimulates urination
- Genitals: Causes erection
Cholinergic Agonists Classified
- Choline esters: Acetylcholine, Carbachol, Methacholine, Bethanechol
- Alkaloids: Muscarine, Nicotine, Lobeline, Pilocarpine, Arecholine, Oxotremorine
Choline Esters Properties
- Acetylcholine: Undergoes rapid hydrolysis
- Acetylcholine: IV bolus injection - effects last 5-20 seconds
- Acetylcholine: IM and SC injections cause local effects
- Methacholine: 3 times more resistant to hydrolysis than ACh, longer duration
- Methacholine: Effective orally
- Bethanechol: Negligible CVS effects, acts primarily on bladder and bowel
- Bethanechol: Preferable to Carbachol due to partial selectivity
- Carbachol: Acts on both muscarinic and nicotinic receptors
- Choline esters are lipid-insoluble, poorly absorbed and poorly penetrate the central nervous system (CNS)
Choline Esters- Clinical Uses
- Bethanechol: Postoperative paralytic ileus, postoperative/postpartum urinary retention, neurogenic bladder atony, congenital megacolon, gastroesophageal reflux
- Other uses: Dry mouth (Sjogren's syndrome with pilocarpine) and diagnosis of bronchial airway hyperreactivity (methacholine)
Adverse Effects
- Excessive salivation, sweating
- Nausea, diarrhea, abdominal cramps
- Urinary urgency
- Cutaneous vasodilation
- Bronchoconstriction
- Hypotension
Contraindications
- Bronchial asthma
- GI or urinary tract obstruction
Alkaloids Notes
- Muscarine: Occurs in poisonous mushrooms, only muscarinic actions, not used therapeutically, toxic when ingested, less well absorbed than tertiary alkaloids
- Pilocarpine, Lobeline, and Nicotine: Tertiary alkaloids, well absorbed, nicotine derived from tobacco, lipophilic, absorb through skin
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
Related Documents
Description
This quiz covers the key concepts of direct-acting cholinergic agonists and their effects on the parasympathetic division. Learn how these agonists, including choline esters and alkaloids, mimic acetylcholine and influence various bodily functions. Test your knowledge on their classification and physiological impacts.
