Dopamine is a substance naturally produced in the body which transmits signals in the brain. It is mainly concerned with mood and behavioral changes. The activity of dopamine is increased in depressive disorders and schizophrenia (thought and behavioral disorder). Levosulpiride acts by blocking the action of dopamine and thereby improve depression. In lower doses, Levosulpiride has gut motility improving properties and is used to treat reflux of stomach acid and stomach movement disorders like constipation, loose motions, etc
Levosulpiride blocks presynaptic dopaminergic receptors. This results in reduced synthesis of dopamine and its release and at higher doses, it causes receptor antagonism at postsynaptic D2. This makes it possible for the drug to treat positive and negative symptoms in schizophrenia.
Domperidone acts as a gastrointestinal emptying (delayed) adjunct and peristaltic stimulant. The gastroprokinetic properties of domperidone are related to its peripheral dopamine receptor blocking properties. Domperidone facilitates gastric emptying and decreases small bowel transit time by increasing esophageal and gastric peristalsis and by lowering esophageal sphincter pressure. Antiemetic: The antiemetic properties of domperidone are related to its dopamine receptor blocking activity at both the chemoreceptor trigger zone and at the gastric level. It has strong affinities for the D2 and D3 dopamine receptors, which are found in the chemoreceptor trigger zone, located just outside the blood brain barrier which - among others - regulates nausea and vomiting.
