Pilocarpine,a cholinomimetic alkaloid Chewing pilocarpus causes salivation.It also induces sweating Action chielly muscarinic HO HC 0 CH2-'N-CH H Muscarine H C-CH2 Pilocarpine Used clinically for treating dry mouth(xerostomia)after radiation therapy of head and neck tumor;also for treatment of glaucoma. Organ effects of cholinergic agonists Eyes:contraction of ciliary muscle and smooth muscle of the iris sphincter(miosis)-aqueous humor outflow, drainage of the anterior chamber Cardiovascular:Bradycardia(possibly preceded by tachycardia),vasodilation(all vascular beds including pulmonary and coronary-M3)and hypotension, reduction of the contraction strength(atrial and ventricular cells,Ikcdiastolic depolarization,NO- inhibitable ATP),negative chronotropic effect (inhibition of adrenergic activation). Respiratory:Bronchoconstriction,mucus secretion 6
6 Pilocarpine, a cholinomimetic alkaloid • Chewing pilocarpus causes salivation. It also induces sweating. • Used clinically for treating dry mouth (xerostomia) after radiation therapy of head and neck tumor; also for treatment of glaucoma. Organ effects of cholinergic agonists • Eyes: contraction of ciliary muscle and smooth muscle of the iris sphincter (miosis) – aqueous humor outflow, drainage of the anterior chamber • Cardiovascular: Bradycardia (possibly preceded by tachycardia), vasodilation (all vascular beds including pulmonary and coronary – M3) and hypotension, reduction of the contraction strength (atrial and ventricular cells, IK+ , ICa2+ diastolic depolarization , NOinhibitable ATP), negative chronotropic effect (inhibition of adrenergic activation). • Respiratory: Bronchoconstriction, mucus secretion
Organ effects of cholinergic agonists GI-increases in tone,amplitude of contractions,and peristaltic activity of the stomach and intestines; enhances secretory activity of the gastrointestinal tract. Urinary bladder-increase ureteral peristalsis,contract the detrusor muscle of the urinary bladder,increase the maximal voluntary voiding pressure,and decrease the capacity of the bladder. Other effects-Increased secretion from all glands that receive parasymphatetic enervation(salivary,lacrimal, tracheobronchial,digestive and exocrine sweat glands) Muscarinic receptor antagonists ATROPINE OH SCOPOLAMINE 00 OH 7
7 • GI - increases in tone, amplitude of contractions, and peristaltic activity of the stomach and intestines; enhances secretory activity of the gastrointestinal tract. • Urinary bladder - increase ureteral peristalsis, contract the detrusor muscle of the urinary bladder, increase the maximal voluntary voiding pressure, and decrease the capacity of the bladder. • Other effects – Increased secretion from all glands that receive parasymphatetic enervation (salivary, lacrimal, tracheobronchial, digestive and exocrine sweat glands) Organ effects of cholinergic agonists Muscarinic receptor antagonists ATROPINE SCOPOLAMINE