Neurotransmitters

1. Neurotransmitters Bibi Kulsoom

2. Nervous System http://archive.ck12.org/ck12/images?id=334457

3. Neuron http://springvisualculture1b.blogspot.com/2010/04/neuron-psychologist.html

4. Neurotransmitter A chemical substance that is • Synthesized in a neuron. • Stored in presynaptic nerve terminal. • Released into synaptic cleft. • Act upon the postsynaptic neuron, muscle or organ. Synthesis of neurotransmitter Axon of a neuron Stored neurotransmitter Presynaptic membrane Axon terminal Postsynaptic membrane Synaptic cleft Postsynaptic membrane receptors Effect specific to target tissue

5. Classification of Neurotransmitters

6. Functional Classification

7. Acetylcholine • Synthesized from acetyl CoA and choline. • Stored in presynaptic terminal • Released into synaptic cleft • Act upon the postsynaptic receptors • Receptors are two types • Muscarinic, 2.Nicotinic • Acetylcholine esterase hydrolyzes acetylcholine. Acetyl CoA + Choline Acetylcholine esterase Muscarinic 2.Nicotinic Effect specific to target tissue

8. Types of Cholinergic Receptors Muscarinic Nicotinic Acetylcholine Acetylcholine http://www.nature.com/npp/journal/v37/n1/images/npp2011199f2.jpg

9. Types of Cholinergic Receptors

10. Distribution of Cholinergic Receptors Peripheral Nervous System CNS Nic Nic Nic ACh ACh Muscarinic Parasympathetic ACh Nictinic: Adrenal medulla Sympathetic ACh NE Adrenergic: Heart and blood vessels ACh ACh Muscarinic: Sweat glands Nicotinic: Skeletal muscles ACh Somatic

11. Myasthenia Gravis http://jama.ama-assn.org/content/vol293/issue15/images/medium/jpg0420f1.jpg

12. 2 H H 2 Catecholamines Epinephrine Catecholaminesare derivatives of tyrosine & contain a catechol (dihydroxybenzene) ring. The difference between epinephrine and norepinephrine: one additional methyl group in structure of epinephrine. The difference between norepinephrine and dopamine: one additional hydroxyl group in the structure of norepinephrine. (Adrenaline) Norepinephrine (Noradrenaline) Dopamine kulsoom http://website.lineone.net/~dave.cushman/epipen.html

13. Sympathetic System Sympathetic Nervous System: Postganglionic nerve fibers Preganglionic nerve fibers Thoracolumber ACh Noradrenaline Target tissue Ganglion Vasodilation Blood Adrenal Medulla: Skeletal muscle Adrenaline Thoracic ACh Noradrenaline Digestive system Adrenal Medulla Vasoconstriction kulsoom

14. Synthesis of Adrenaline and Noradrenaline Adrenal Medulla Synthesis of Adrenaline & Noradrenaline Synthesis of Adrenaline & Noradrenaline Phenylalanine Hydroxylase Sympathetic Nerve Tyrosine Hydroxylase DOPA decarboxylase Dopamine Hydroxylase Phenylethanolamine N-Methyltransferase Effect specific to target tissue

15. Mechanism of Action http://www.sp.uconn.edu/~bi107vc/images/anim/SigtranRA.gif

16. Adrenergic Receptor Beta Alpha kulsoom Alpha 1 Alpha 2 Beta 1 Beta 2 Beta 3 Adrenergic receptors are seven-pass transmembrane proteins. kulsoom

17. Mechanism of Action • These are called G protein-coupled receptors (GPCRs). • The three subunits are: Gα, Gβ, Gγ • Gα carries the binding site for the nucleotide and is different in different types of G proteins Gs, Gi and Gq.  Gα β  β Giα Gsα Gqα • Gβ and Gγ are same in all types of G proteins. http://withfriendship.com/images/c/14666/Adrenergic-receptor-wallpaper.gif

18. Distribution of Adrenergic Receptor

19. = Adrenaline & Noradrenaline  1 2 Gq Gs Gi Phospholipace C Adenylate cyclase Adenylate cyclase DAG PIP2 cAMP cAMP IP3 Decreased Increased Decreased Increased Ca2+ Ca2+ Inhibition of neurotransmitter release from neuron • Glycogen breakdown • Smooth muscle relaxes • Cardiac muscle contracts Smooth muscle Contraction Smooth muscle Contraction Effector cell kulsoom = leading to = inhibits

20. Effect of Autonomic NS on Heart Parasympathetic Nerves (Vagus) Sympathetic Nerves & Norepinephrine ACh NE 1 2 M2 ↑ heart rate ↑ conduction velocity ↑contractility ↑ rate of myocyte relaxation _ + Cardiomyocyte http://www.cvphysiology.com/Blood%20Pressure/BP010.htm Kulsoom animated from http://www.cvphysiology.com/Blood%20Pressure/BP010.htm http://bioserv.fiu.edu/~walterm/fund_sp2004/heart/f12-20_baroreceptor_and_c.jpg

21. Distribution of Adrenergic Receptor E = Epinephrine At low epinephrine concentrations, the beta-2 adrenergic receptors will be occupied because these receptors have a higher affinity for epinephrine. At high epinephrine concentrations, the alpha-1 adrenergic receptors will be occupied too. Because there are more alpha-1 receptors the predominant effect at high epinephrine concentration is vascular smooth muscle contraction. kulsoom

22. Dopamine http://it.wikipedia.org/wiki/File:Dopamine_chemical_structure.png

23. Glycine NMDA=N-methyl-D-aspartate http://o.quizlet.com/i/I8RJX-RlIpAe58vmHdpL0w_m.jpg

24. Aspartic Acid L-Aspartate NMDA=N-methyl-D-aspartate http://0.tqn.com/d/chemistry/1/7/V/V/1/L-aspartic_acid.png

25. Glutamate Glutamate AMPA = amino-methyl propanoic acid

26. -aminobutyric acid (GABA) CO2 Synthesis: Glutamate decarboxylase -aminobutyric acid (GABA) Glutamate

27. Serotonin Synthesis: Hydroxylation & decarboxylation Serotonin (5-hydroxytryptamine) Tryptophan http://www.wormatlas.org/neurotransmitterstable.htm

28. Histamine Histidine Histamine http://web.campbell.edu/faculty/nemecz/323_lect/Nitrogen_metabolism/images/histamine.jpg

29. Neuropeptides There are around 200 neuropeptides identified.

30. Miscellaneous Neurotransmitters • ATP: • Is found in both the CNS and PNS • Produces excitatory or inhibitory responses depending on receptor type. • Induces Ca2+ wave propagation in astrocytes • Provokes pain sensation • Nitric oxide (NO) : • Activates the intracellular receptor guanylyl cyclase • involved in learning and memory. • Carbon monoxide (CO): • a main regulator of cGMP in the brain

31. Subhan Allah http://myyatradiary.blogspot.com/2011/08/treks-beyond-badrinath-swargarohini.html