Motility Agents and Antiemetics Flashcards
How do enterochromaffin cells respond to increased pressure?
By increasing serotonin release
What does released serotonin activate?
Sensory neurons leading to CNS and sensory leading to enteric nervous system
What are 5-HT3 receptors?
Serotonin receptors on the sensory neurons leading to the CNS
What are 5-HT4 receptors?
Serotonin receptors on the pre-synaptic receptors of sensory neurons going to ENS
What gives positive input to postganglionic PS neurons?
Motilin receptor
Ach
Serotonin 5-HT4 receptor
What gives negative input to postganglionic PS neurons?
DA2 dopamine receptor
What type of M3 receptors are there?
Agonists
Antagonists
What type of dopamine-2 receptors are there?
Antagonist
What type of motilin receptors are there?
Agonists
What act on M3 receptor agonist and antagonist respectively?
Agonist: bethanacol
Antagonists: anticholinergics
What acts on dopamine antagonist receptors?
Metoclopramide
What acts on motilin receptor agonists?
Macrolides (antibiotics)
What type of drug is bethanacol?
M3 agonist anticholinesterase (multiple side effects)
What is metoclopramide?
D-2 receptor antagonists
What is a potential side effect of metoclopramide?
Parkinsonism (Parkinson like properties)
Where are motilin receptors found?
Postganglionic PS neuron
Intestinal SM
What do the higher centers for emesis respond to?
Smells
Stress/anticipation
What do the vestibular centers for emesis respond to?
Motion sickness
Visual stimuli
What are the vagal afferent stimuli for emesis?
Mechanoreceptors
5-HT
Chemoreceptors
What does CTZ in emesis stand for?
Chemoreceptor trigger zone
What are the vestibular receptors for emesis?
Histamine-1 receptors
Muscarinic-1 receptors
