Question

List cholinergic responses not normally caused when usual therapeutic doses of a muscarinic agonist are administered and why these effects do not occur.

Answer 1

Answer: Muscarinic agonists produce contraction of the iris sphincter muscle, producing a small pupil diameter (miosis), and contraction of the ciliary muscle, which opens the trabecular network to allow increased outflow of aqueous humor through the canal of Schlemm.

• Decrease intraoccular pressure by constricting pupil and contracting ciliary bodies of the eyes
• Heart brake: lower heart rate, decrease output, lowers BP
• Dilates blood vessels Skin, Viscera, Mucus Membranes (GI)
• Increase tone and motility of GI smooth muscles
• Increase peristalsis
• Contraction of the detruser muscle bladder increase bladder pressure and relaxes trigone and bladder sphincter = urination