serotonin

review

synthitic - tryptophan

stpred in enterochromaffin cells in GIT and brain

can’t pass CNS

converted to melatonin in pineal body

metabolized by MAO → increased in carcinoid tumors and respire therapy

acts as chemical transmitter in brain and may be involved in regulation of body tempreture - mood - appetite - pain perception - blood pressure control - depression

VC - platelet aggregation

peristaltic reflex - allergic reaction - carcinoid syndrome

serotonin receptors

5HT1 A-BD-E-F

5HT A-B-C

5HT3-4-5-6-7

5HT4

5HT5

5HT A-B-D-E-F

inhibit adenylcyclase - present in CNS

5HT2 A B C

activate PLC - smooth muscles

platelets - CNS

5HT3 4 5 6 7

CNS - peripheral nerves

5HT4

increase ACh release in GUT

5HT5

CNS

actions

cardio-vascular system → VC of BV and VD of skeletal muscles BV

stimulation heart - increased platelet aggregation

smooth muscles → spasmogenic effect

antiduretic effect → VC of afferent renal arterioles

ganglion stimulant action - stimulation of sensory nerve endings

serotonin agonists

buspirone

sumatriptan - zolmitriptan

dexfenfluramine

fluoxitine - fluvoxamine

mosapride

buspirone

partial agonist on 5HT1A receptor

used as anxiolytic

sumatriptan - zolmitriptan

5HT1D mediates VC

oral or SC tratment of migraine attacks

side effects : tingling - dizziness - neck pain - chest pain

contraindications : angina - hypertension - PVD -pregnancy

short duration → requires multiple doses but inly allowed 2/24 hours

dexfenfluramine

appetite suppressant

fluoxetine - fluvoxamine

serotonin reuptake inhibtor

mosapride

5HT4

prokinetic agent

cyproheptadime

actions → 5HT2 blockade

H1 - muscarinic receptors blockade

side effects → drowsiness - dry mouth

uses → allergy - carcinoid tumors - prophylaxis of migraine

ondasetron

prevent nausea and vomiting in cancer chemotherapy