<prompt> Which one of the following drugs increases gastrointestinal motility?GlycopyrrolateFentanylAtropineNeostigmine  <response>: Neostigmine belongs to group Anticholinesterases anti-ChEs which are the agents which inhibit ChE, protect ACh from hydrolysis-produce cholinergic effects in vivo and potentiate ACh, both in vivo and in vitro. Quaternary ammonium anti-ChEs like neostigmine have additional direct action on nicotinic cholinoceptors. ACTIONS of AchSmooth muscle in most organs is contracted mainly through M3 receptors. Tone and peristalsis in the gastrointestinal tract is increased and sphincters relax leading to abdominal cramps and evacuation of bowel.Thus, Neostigmine increases gastrointestinal motility.Reference: Essentials of Medical Pharmacology Eighth Edition KD TRIPATHI page no 114,117 