Detailed presentation of acetylcholine and dopamine.pptx

This presentation explores Acetylcholine — the first identified neurotransmitter — covering its biosynthesis, release, receptor types, and mechanisms of action. It explains its vital role in memory, muscle contraction, and autonomic function, along with associated disorders and pharmacological modulation by drugs.
This presentation provides a detailed overview of Dopamine — a key neurotransmitter in the brain’s reward, motivation, and motor pathways. It covers its synthesis, receptor types, physiological roles, and involvement in disorders like Parkinson’s disease, schizophrenia, and addiction, with pharmacological insights.

1. ACETYLCHOLINE AND DOPAMINE Presented by : Masooma Zahra Roll No. 052 Subj: Pharmacology Presented to: Dr. Waleed

2. Introduction to Acetylcholine (Ach) Definition : Acetylcholine (\text{Ach}) is the first neurotransmitter discovered and serves as the primary chemical messenger for the cholinergic system. Key Locations and Roles : Somatic Nervous System (SNS): Essential for voluntary movement at the Neuromuscular Junction (NMJ). Parasympathetic Nervous System (PNS): Used by all pre-ganglionic and all post-ganglionic neurons (the “Rest and Digest” system). Sympathetic Nervous System ( SNS ): Used by all pre-ganglionic neurons. Central Nervous System ( CNS ): Critical for cognitive functions, including memory, learning, and sleep regulations

3. SYNTHESIS AND METABOLISM:

4. LOCATION & FUNCTIONS OF ACHRS

5. FUNCTIONS AND LOCATION OF NICOTINIC RECEPTORS.

6. Acetylcholine Agonists - Muscarinic agonists (e.g., Pilocarpine, Bethanechol): smooth muscle contraction, glandular secretion, heart rate regulation - Nicotinic agonists (e.g., Nicotine, Varenicline): muscle contraction, neurotransmission, cognitive functions.

7. ACETYLCHOLINE ANTAGONIST - Muscarinic antagonists (e.g., Atropine, Scopolamine): block mAChRs, used for:
- Bradycardia
- Respiratory disorders (e.g., COPD)
- Gastrointestinal disorders (e.g., peptic ulcer) - Nicotinic antagonists (e.g., Tubocurarine, Vecuronium): block nAChRs, used for:
- Muscle relaxation (surgery)
- Neuromuscular blockade

8. CLINICAL SIGNIFICANCE AND PHARMACOLOGICAL IMP OF ACH Therapeutic targets : AChE inhibitors, muscarinic agonists/antagonists, and nicotinic agonists/antagonists used for various disorders- Neurological disorders : Alzheimer's disease, Parkinson's disease, myasthenia gravis, and schizophrenia- Cardiovascular effects : regulation of heart rate and blood pressure- Gastrointestinal effects : regulation of gut motility and secretion- Respiratory effects : regulation of bronchial tone and secretion

9. Dopamine: The Reward Neurotransmitter - Catecholamine neurotransmitter involved in motivation, reward, and pleasure processing
- Plays a role in movement, emotion, and cognition
- Referred to as the “feel-good” hormone
- Dysregulation implicated in Parkinson’s disease, schizophrenia, and addiction

10. SYNTHESIS AND METABOLISM OF DOPAMINE TH- tyrosine hydroxylase convert tyrosine into L-dopa L-dopa converted to dopamine by AADC ( Aromatic L-Amino Acid Decarboxylase) Dopamine packaged into vesicles via VMAT . Dopamine binds to D1 and D2 . Signal transferred in the form of cAMP . Taken up by DAT . D2 receptors control release of dopamine

11. DOPAMINE RECEPTORS: Dopamine Receptors - *D1*: Located in striatum and cortex, involved in motor function and working memory - *D2*: Found in striatum and nucleus accumbens, plays a role in motor control and reward processing - *D3*: Present in limbic regions, influences emotion and motivation
- *D4*: Located in cortex and hippocampus, involved in cognition and emotion
- *D5*: Found in hippocampus and hypothalamus, contributes to memory and emotion

12. Common Diseases Involving Dopamine Dysregulation and Their Physiology PARKINSON DISEASE: Degeneration of dopaminergic neurons in substantia nigra → decreased striatal dopamine → motor symptoms (tremors, bradykinesia, rigidity) A ddiction: Repeated substance use → increased dopamine release in nucleus accumbens → reinforcement and compulsive seeking → long-term adaptations in reward circuitry ADHD: (Attention Deficit Hyperactivity Disorder)*: Dopamine dysfunction in prefrontal cortex and striatum → impaired attention, motivation, and impulse control Depression: Decreased dopamine in mesolimbic pathway → anhedonia, motivational deficits, and pleasure reduction

13. CLINICAL STRATEGIES FOR DOPAMINE DYSREGULATION *Parkinson’s Disease*: - Levodopa (dopamine precursor) - Dopamine agonists (e.g., pramipexole, ropinirole)
- MAO-B inhibitors (e.g., selegiline) - *Addiction *:
- Behavioral therapies (e.g., CBT)
- Medications for withdrawal management (e.g., naltrexone, bupropion)
- * ADHD*: - Stimulants (e.g., methylphenidate, amphetamines)
- Non-stimulants (e.g., atomoxetine) *Depression*: - Dopamine agonists (e.g., pramipexole)
- Antidepressants with dopaminergic activity (e.g., bupropion)
.

14. REFRENCE: #Katzung’s Basic & Clinical Pharmacology*:
Chapter 21: Dopamine & Other Biogenic Amines (13 th edition #Lippincott’s Illustrated Reviews: Pharmacology*:
Chapter 13: Central Nervous System Pharmacology (6 th edition)