Download Free Medical CNS INTRODUCTION PowerPoint Presentation

CNS INTRODUCTION PowerPoint Presentation

DOWNLOAD MEDICAL POWERPOINT PRESENTATION

About This Presentation

Description : Check out this medical presentation on Neurology, which is titled "CNS INTRODUCTION", to know about Central Nervous System (CNS).

Tags : Neurology, Central Nervous System, CNS

Published on : Aug 23, 2021 | Views : 2307 | Downloads : 9

Shareable Url :

Embed Code :

Comment

Transcript

Slide 1-

CNS INTRODUCTION
Slide 2-

Parkinson’s disease: ↓ Dopamine (relatively ↑ Acetylcholine) Depression: ↓ Serotonin, ↓ NA Schizophrenia: ↑ Dopamine
Slide 3-

Introduction Nearly all drugs with CNS effects act on specific receptors that modulate synaptic transmission. A very few agents such as general anesthetics and alcohol may have nonspecific actions on membranes, but even these non–receptor-mediated actions result in demonstrable alterations in synaptic transmission.
Slide 4-

CNS Cerebrum Subcortical region Thalamus hypothalamus Mid brain Hind brain Pons Medulla cerebellum Spinal cord
Slide 5-

Cerebrum Frontal cortex Parietal lobe Temporal lobe Occipital lobe
Slide 6-

Subcortical Region Thalamus act as relays between incoming sensory pathways and the cortex Hypothalamus The hypothalamus is the principal integrating region for the autonomic nervous system and regulates body temperature, water balance, intermediary metabolism, blood pressure, sexual and circadian cycles, secretion from the adenohypophysis, sleep, and emotion. Limbic system
Slide 7-

Limbic system-The limbic system is an archaic term for an assembly of brain regions (hippocampal formation, amygdaloid complex, olfactory nuclei, basal ganglia, and selected nuclei of the diencephalon) grouped around the subcortical borders of the underlying brain core.
Slide 8-

Pons – motor & sensory control, consciousness & sleep Medulla- breathing, heart rate Cerebellum- maintaining the proper tone of antigravity musculature and providing continuous feedback during volitional movements of the trunk and extremities. Spinal cord- integrates sensory & motor reflexes, controls muscle tone.
Slide 9-

Neurons
Slide 10-

Support cells of neurons Macroglia – astrocytes & oligodendroglia Microglia -astrocytes (cells interposed between the vasculature and the neurons, often surrounding individual compartments of synaptic complexes). Astrocytes play a variety of metabolic support roles including furnishing energy intermediates and supplementary removal of neurotransmitters following release.
Slide 11-

oligodendroglia, a second prominent category of macroglia, are myelin-producing cells. Myelin, made up of multiple layers of compacted membranes, insulate segments of axons bioelectrically and permit non-decremental propagation of action potentials.
Slide 12-

Microglia- related to the macrophage/monocyte lineage. Some microglia reside within the brain, while additional cells of this class may be recruited to the brain during periods of inflammation following either microbial infection or brain injury.
Slide 13-

Blood-Brain Barrier (BBB) boundary between the periphery and the CNS that forms a permeability barrier to the passive diffusion of substances from the bloodstream into the CNS. An exception exists for lipophilic molecules, which diffuse fairly freely across the BBB and accumulate in the brain.
Slide 14-

Organs not covered by BBB- median eminence area postrema (CTZ) pineal gland pituitary gland choroid plexus capillaries
Slide 15-

Central Neurotransmitters Acetylcholine Amines Dopamine, NE, E, Serotonin, Histamine Amino acids Glutamate, Aspartate (excitatory) GABA, Glycine (inhibitory) Peptides Oxytocin, Tachykinins, VIP, Opioid peptides NO Miscellaneous Anandamide, Adenosine, ATP
Slide 16-

Acetylcholine -cerebral cortex, cerebellum, spinal cord -Receptors- muscarinic & Nicotinic -Functions- arousal, respiration, motor activity, vertigo, memory Amines (Dopamine, NE, E, Serotonin, Histamine) Dopamine -hypothalamus, pituitary (intermediate lobe), substantia nigra, limbic structures, basal ganglia -Receptors- D1, D2, D3, D4, D5 Parkinson’s disease- ↓ DA in basal ganglia Schizophrenia-↑ DA in mesolimbic-mesocortical-mesofrontal pathway
Slide 17-

ppt slide no 17 content not found
Slide 18-

The three major dopaminergic projections in the CNS 1. Mesostriatal (or nigrostriatal) pathway. Neurons in the substantia nigra pars compacta (SNc) project to the dorsal striatum (upward dashed blue arrows); this is the pathway that degenerates in Parkinson disease. 2. Neurons in the ventral tegmental area project to the ventral striatum (nucleus accumbens), olfactory bulb, amygdala, hippocampus, orbital and medial prefrontal cortex, and cinguate gyrus (solid blue arrows). 3. Neurons in the arcuate nucleus of the hypothalamus project by the tuberoinfundibular pathway in the hypothalamus, from which DA is delivered to the anterior pituitary (red arrows).
Slide 19-

NE -Locus ceruleus (pons & reticular formation), cortex, cerebellum -Modulate affective disorders, learning, memory, arousal E -Reticular formation Serotonin -Raphe nuclei of brain stem -Role in nociception, schizophrenia, depression, eating disorders, temp. regulation Histamine -Posterior hypothalamus, cortex, limbic system, brain stem -H1 -Role in arousal, regulation of food and water intake
Slide 20-

Amino acids Glutamate, Aspartate (excitatory) -Cortex , basal ganglia -Receptors- NMDA, AMPA, Kainate, AP-4, ACPD -Synaptic plasticity, neurotoxicity
Slide 21-

ppt slide no 21 content not found
Slide 22-

GABA, Glycine (inhibitory) -GABA present uniformly in brain -Receptors- GABAA (ligand-gated Cl– ion channel, an ionotropic receptor) GABAB is a GPCR - ↑ GABAergic activity- sedation, amnesia, muscle relaxation, ataxia
Slide 23-

ppt slide no 23 content not found
Slide 24-

Peptides Oxytocin, Tachykinins, VIP, Opioid peptides NO Miscellaneous Anandamide, Adenosine, ATP
Slide 25-

Neurochemical Transmission Transmitter synthesis. Small molecules like ACh and NE are synthesized in nerve terminals; peptides are synthesized in cell bodies and transported to nerve terminals. Transmitter storage. Synaptic vesicles store transmitters, often in association with various proteins and frequently with ATP. Transmitter release. Release of transmitter occurs by exocytosis. Depolarization results in an influx of Ca2+, which in turn appears to bind to proteins called synaptotagmins.
Slide 26-

Transmitter recognition. Receptors exist on postsynaptic cells, which recognize the transmitter. Binding of a neurotransmitter to its receptor initiates a signal transduction event. Termination of action. -hydrolysis (for acetylcholine and peptides) -reuptake into neurons by specific transporters such as NET, SERT, and DAT (for NE, 5-HT, DA). -Inhibitors of NET, SERT, and DAT increase the dwell time and thus the effect of those transmitters in the synaptic cleft. -Inhibitors of the uptake of NE and/or 5-HT are used to treat depression and other behavioral disorders
Slide 27-

Neurotransmission
Slide 28-

Depolarization opens voltage-dependent Ca2+ channels in the presynaptic nerve terminal. the influx of Ca2+ during an action potential (AP) triggers the exocytosis of small synaptic vesicles that store neurotransmitter (NT) involved in fast neurotransmission. Released neurotransmitter interacts with receptors in the postsynaptic membranes that either couple directly with ion channels or act through second messengers, such as GPCRs. Neurotransmitter receptors in the presynaptic nerve terminal membrane can inhibit or enhance subsequent exocytosis.
Slide 29-

Released neurotransmitter is inactivated by reuptake into the nerve terminal by a transport protein coupled to the Na+ gradient, for example, DA, NE, and GABA; by degradation (ACh, peptides); or by uptake and metabolism by glial cells (Glu). The synaptic vesicle membrane is recycled by clathrin-mediated endocytosis. Neuropeptides and proteins are stored in larger, dense core granules within the nerve terminal. These dense core granules are released from sites distinct from active zones after repetitive stimulation.
Slide 30-

Neurotransmitters The transmitter must be present in the presynaptic terminals of the synapse. The transmitter must be released from the presynaptic nerve concomitantly with presynaptic nerve activity. When applied experimentally to target cells, the effects of the putative transmitter must be identical to the effects of stimulating the presynaptic pathway. Specific pharmacological agonists and antagonists should mimic and antagonize, respectively, the measured functions of the putative transmitter with appropriate affinities and order of potency.
Slide 31-

ppt slide no 31 content not found
Slide 32-

ppt slide no 32 content not found
Slide 33-

Neurohormones Hypothalamic neurons affecting the anterior pituitary release their hormones into the hypothalamic–adenohypophyseal portal blood system, which delivers them to the anterior pituitary, where they regulate the release of trophic hormones (i.e., ACTH, FSH, GH, LH, prolactin) into the blood. Other hypothalamic neurons project onto the posterior pituitary, where they release their peptide contents, oxytocin and arginine vasopression (anti-diuretic hormone, or ADH) into the systemic circulation.
Slide 34-

ppt slide no 34 content not found
Slide 35-

Neuromodulators The distinctive feature of a modulator is that it originates from non-synaptic sites, yet influences the excitability of nerve cells. Substances such as CO, ammonia, neurosteroids, locally released adenosine, prostaglandins, and nitric oxide (NO). Neuromodulation relates to synaptic plasticity.
Slide 36-

Neurotrophic Factors Neurotrophic factors are substances produced within the CNS by neurons, astrocytes, microglia. These act over a longer time scale than neuromodulators to regulate the growth and morphology of neurons. The binding of neurotrophic factors to their receptors generally promotes receptor dimerization and protein tyrosine kinase activity in the intracellular domains of the receptors.
Slide 37-

ppt slide no 37 content not found
Slide 38-

Categories of neurotrophic peptides: classic neurotrophins -nerve growth factor -brain-derived neurotrophic factor (BDNF) growth factor peptides, -epidermal growth factor -activin A -fibroblast growth factors -insulin-like growth factors -platelet-derived growth factors
Slide 39-

Central Neurotransmitters Acetylcholine Amines Dopamine, NE, E, Serotonin, Histamine Amino acids Glutamate, Aspartate (excitatory) GABA, Glycine (inhibitory) Peptides Oxytocin, Tachykinins, VIP, Opioid peptides NO Miscellaneous Anandamide, Adenosine, ATP
Slide 40-

MCQs Q1. Drugs can NOT diffuse freely across the A. the median eminence B. area postrema C. striatum D.pineal gland Ans-C
Slide 41-

Q2. Which of the following is an inhibitory amino acid neurotransmitter? A. glutamate B. GABA C. aspartate D. PABA Ans- B
Slide 42-

Q3. The difference in concentration of a drug in blood from its concentration in brain after oral administration is due to: A. preservatives used in drugs B. blood brain barrier C. liver metabolism D. incomplete absorption of drug Ans- B
Slide 43-

Q4. Which of the following factor facilitates drugs diffusion fairly freely across the BBB (blood brain barrier )? A. lipophobic B. bioavailability C. lipophilic D. t 1/2 (half life) Ans- C
Slide 44-

Q5. Which of the following is excitatory neurotransmitter? A. Glutamate B. GABA C. Dopamine D. Glycine Ans- A
Slide 45-

Q6. GABAA receptor is a A. ionotropic receptor B. G-protein coupled receptor C. voltage gated channel D. kinase linked receptor Ans- A
Slide 46-

Q7. GABAB receptor is a A. ionotropic receptor B. metabotropic receptor C. voltage gated channel D. kinase linked receptor Ans- B
Slide 47-

Q8. In cell signaling and synaptic transmission, the chemical that originates from non-synaptic sites, yet influences the excitability of nerve cells is A. neurotrophic factor B. neurohormone C. neuromodulator D. neuromediators Ans- C
Slide 48-

Q9. Which of the following factors does NOT govern passage of drug across biological membranes? A. charge B. lipophilicity C. the presence or absence of energy-dependent transport systems D. t 1/2 (half life) Ans- D
Slide 49-

Q 10. Which of the following is NOT a criteria for Neurotransmitter: transmitter must be present in the presynaptic terminals of the synapse. The transmitter must be released from the presynaptic nerve concomitantly with presynaptic nerve activity. When applied experimentally, effects must be identical to the effects of stimulating the presynaptic pathway. Should be an excitatory transmitter. Ans- D
Slide 50-

Thank you
Slide 51-

Bibliography Essentials of Medical Pharmacology -7th edition by KD Tripathi Goodman & Gilman's the Pharmacological Basis of Therapeutics 12th edition by Laurence Brunton (Editor) Lippincott's Illustrated Reviews: Pharmacology - 6th edition by Richard A. Harvey Basic and Clinical pharmacology 11th edition by Bertram G Katzung Rang & Dale's Pharmacology -7th edition by Humphrey P. Rang Clinical Pharmacology 11th edition By Bennett and Brown, Churchill Livingstone Principles of Pharmacology 2nd edition by HL Sharma and KK Sharma Review of Pharmacology by Gobind Sparsh