Possible Interaction: Acetylcholine and Quinidine

“Armitage2 has suggested that quinidine impairs repolarization by rendering the cell membrane less permeable to potassium ions, and acetylcholine restarts the tissue by restoring the potassium permeability.”

“… ACh controls the initiation and conduction of the contractions has been provided by Burn & Kottegoda (1953) who have studied the effect of eserine on the … of eserine on the cholinesterase in the auricles, and by Briscoe & Burn (1954) who have studied the action of other anticholinesterases and of quinidine ….”

“ Acetylcholine may make atrial cells more sensitive to the effects of quinidine.”

“The initial K+ efflux transient induced by ACh was inhibited by quinine (0.1–3 mmol/l), quinidine (1–3 mmol/l) and Ba2+ (5 mmol/l), but not by verapamil (0.1 mmol/l), lidocaine (1 mmol/l), 4-aminopyridine (1 mmol/l) or apamin (1 μmol/l).”

“… quinidine (2–10 μg/ml) … acetylcholine in proportion to the dose.3.Infusion of postglandin E1 (10 ng/ml) in addition to mepacrine or quinidine restores the inhibited … by inhibiting the release of E-type prostaglandins which sensitize pain receptors and secondarily by an unspecific antagonism (local-anaesthetic action).”

“These effects of ACh were abolished by tetrodotoxin or quinidine as well as by atropine.”

“ Quinidine inhibited the ATP response and blocked the inhibitory effect of ATP on acetylcholine , potassium-depolarization and field-stimulation responses.”

“3 Pretreatment with quinidine (2 μm) selectively blocked the acetylcholine (ACh)‐induced depolarization which was recorded in the multicellular tissues by a conventional intracellular microelectrode technique.”

“Theophylline and quinidine ('purinoceptor' antagonists) antagonized ACH contractile effects and so could not be satisfactorily employed in the characterization of the purine receptors in the mouse rectum.”

“ Quinidine (26-264 M) abolished the responses to ATP and acetylcholine , while indomethacin (28 microM) and theophylline (55 microM) antagonized only the acetylcholine responses.”