Dopamine - monoamines presentation part 1
- 1. DOPAMINE By :- Dr. Manan Parmar 1st Year PG resident M.G.M. Medical College, Indore
- 2. DOPAMINE Definition Dopamine is a neurotransmitter involved in central and peripheral nervous system functions. Synthesis Synthesized from tyrosine via the intermediate L- DOPA. Metabolism Metabolized by MAO and COMT into 3-MT and DOPAC.
- 3. DOPAMINE PATHWAYS IN THE BRAIN 1 Nigrostriatal Pathway Controls motor functions; degeneration leads to Parkinson's disease. 2 Mesolimbic Pathway Involved in reward, pleasure, and addiction; hyperactivity implicated in schizophrenia. 3 Mesocortical Pathway Involved in cognition, motivation, and emotional responses; hypoactivity implicated in negative symptoms of schizophrenia. 4 Tuberoinfundibular Pathway Regulates prolactin secretion; dopamine inhibits prolactin release.
- 4. DOPAMINE RECEPTORS D1-like Receptors Stimulate adenylyl cyclase, increasing cAMP. D2-like Receptors Inhibit adenylyl cyclase, decreasing cAMP. Receptor Functions Motor control, reward, cognition, endocrine regulation.
- 5. DOPAMINE RECEPTORS - FUNCTIONS • Motor Function: D1 and D2 receptors regulate voluntary movement; dysfunction leads to disorders like Parkinson's disease. • Reward and Reinforcement: D1-like receptors in the mesolimbic pathway mediate pleasure and motivation. • Cognition: D1-like receptors are involved in working memory and decision-making processes. • Endocrine Regulation: D2 receptors inhibit prolactin release from the pituitary gland.
- 6. PERIPHERAL ACTIONS OF DOPAMINE Kidneys Dopamine receptors control renal blood flow and sodium excretion, helping to maintain healthy blood pressure. Cardiovascul ar System Cardiac dopamine receptors modulate heart rate and contractility, it increases cardiac output but there is no change in the mean blood pressure. Gastrointesti nal Tract Dopamine influences gut motility and secretion. Endocrine System Dopamine inhibits the release of prolactin from the pituitary gland, regulating important hormonal processes.
- 7. CLINICAL RELEVANCE PARKINSON'S DISEASE Medications like levodopa, dopamine agonists, COMT inhibitors, and MAO-B inhibitors are used to manage the symptoms of Parkinson's disease. SCHIZOPHRENIA Typical and atypical antipsychotics target D2 receptors to help manage the positive symptoms of schizophrenia.
- 8. CLINICAL RELEVANCE 1) Neurological Bias 2) Reward pathway 3) Treatment Strategy 4) Neurobiology of Addiction :- A) Mesolimbic dopamine system B) Reward Circuit C) Neuro-adaptation D) Treatment ADDICTION
- 9. CLASSIFICATION OF DOPAMINE AGONISTS Ergot Derivatives Drugs like Bromocriptine and Cabergoline. Non-Ergot Derivatives Pramipexole, Ropinirole, and Rotigotine.
- 10. DOPAMINE AGONISTS Mechanism of Action Activate dopamine receptors directly. Uses Parkinson's Disease, Restless Legs Syndrome, Prolactinomas, Hyperprolactinemia, Hypotension, and Neurological/Psychiatric Disorders, Tourette's syndrome and Huntington Chorea.
- 11. DOPAMINE AGONISTS - SIDE EFFECTS Common Side Effects Nausea, vomiting, dizziness, orthostatic hypotension. Serious Side Effects Hallucinations, impulse control disorders.
- 12. CLASSIFICATION OF DOPAMINE ANTAGONISTS First-Generation Antipsychotics Haloperidol, Chlorpromazine Second-Generation Antipsychotics Risperidone, Olanzapine, Quetiapine, Aripiprazole Other Dopamine Antagonists Metoclopramide, Prochlorperazine, Domperidone
- 13. DOPAMINE ANTAGONISTS • Mechanism of Action: Block dopamine receptors, reducing dopaminergic activity. • Uses: Antipsychotic Treatment, Antiemetic Treatment, Hyperprolactinemia, Management of Tourette Syndrome, Hyperactivity and Agitation, Hypertension.
- 14. DOPAMINE ANTAGONISTS - DRUGS AND USES First-Generation Antipsychotics Haloperidol is a typical antipsychotic primarily used in the treatment of schizophrenia. Chlorpromazine is used in schizophrenia and as an antiemetic. Second-Generation Antipsychotics Risperidone is used in schizophrenia and bipolar disorder. Olanzapine, Quetiapine and Aripiprazole are used in schizophrenia, bipolar disorder, and depression. Other Uses Metoclopramide and Prochlorperazine are used as antiemetics. Domperidone is a prokinetic agent and antiemetic.
- 15. POTENTIAL SIDE EFFECTS OF DOPAMINE ANTAGONISTS Sedation Weight Gain Tardive Dyskinesia Neuroleptic Malignant Syndrome
- 16. DOPAMINE REGULATION: A CRITICAL ROLE Vital Neurotransmitter Dopamine has far-reaching effects on motor function, reward, cognition, and emotion. Careful Modulation Pharmacological agents are crucial for treating neurological and psychiatric disorders. Complexity Requires An individualized treatment approach with close patient monitoring. Optimize Outcomes Adjust medication regimens to minimize side effects.
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