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some controversy…….. Muscarinic agonists – Muscarine.

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Presentation on theme: "some controversy…….. Muscarinic agonists – Muscarine."— Presentation transcript:

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2 some controversy……..

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4 Muscarinic agonists – Muscarine

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6 some controversy…….. Muscarinic agonists – Muscarine Muscarinic antagonists Synthetic and natural-

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8 DA – dopamine NE – norepinephrine 5HT - serotonin monoamines

9 NE and E are synthesized from their precursor DA with the appropriate enzymes present catecholamines

10 tyrosine hydroxylase- rate limiting step

11 tyrosine hydroxylase DA decarboxylase

12 tyrosine hydroxylase DA decarboxylase DA β hydroxylase PNMT

13 CNS - reward, movement, motivated behaviors, executive function? numerous DA pathways in CNS of importance for psychotropics….. DA (dopamine)

14 DA receptor subtypes – 2 major families – D1 and D2 families DA receptor subtypes

15 In CNS- arousal; role in depression, possible role in spinal analgesia, possible motivated behaviors such as hunger, thirst, sex, anxiety, drug reward? NE is in both the CNS and PNS NE (norepinephrine)

16 receptor subtypes – alpha 1 and 2; β 1 – 3 NE receptor subtypes

17 Catecholamines removed by reuptake: – DAT – DA transporter – NET – NE transporter How are catecholamines taken removed from the synapse?

18 metabolism – – far slower than ACh by AChE metabolism

19 metabolism – – far slower than ACh by AChE – MAO enzymes (monoamine oxidase) metabolism

20 metabolism – – far slower than ACh by AChE – MAO enzymes (monoamine oxidase) MAOA AND MAOB enzymes MAO A – more selective for NE and 5HT metabolism

21 metabolism – – far slower than ACh by AChE – MAO enzymes (monoamine oxidase) MAOA AND MAOB enzymes MAO A – more selective for NE and 5HT MAO B- more selective for DA metabolism

22 Major metabolites: – Important when trying to study potential differences – DA - dopac and HVA – NE - MHPG -(3-methoxy-4-hydroxy- phenethyleneglycol)

23 Tyrosine Tyrosine hydroxylase (rate limiting step) TH DOPA DA- β -hydroxylase Dopamine (DA) Norepinephrine (NE) Epinephrine (E) Aromatic acid decarboxylase mao homovanillic acid (HVA) pnmt catecholamines MHPG mao

24 more recent in our history of studying NT similarity to LSD found early in high concentrations in the gut found in many non neuronal cells (only ~ 1 – 2% of 5HT in whole body is in brain) cannot cross bbb so…… 5HT

25 behavioral role (CNS): sleep, aggressive behavior abnormal function implicated in: – schizophrenia, depression, phobic disorders, OCD, eating disorders, migraine, etc 5HT

26 synthesis – amino acid precursor – tryptophan 5HT

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28 synthesis – amino acid precursor – tryptophan – elimination of dietary tryptophan can significantly lower brain 5HT levels 5HT

29 synthesis – amino acid precursor – tryptophan – elimination of dietary tryptophan can significantly lower brain 5HT levels – foods high in tryptophan; nuts (ie walnuts, almonds), tofu, milk, eggs, certain cheeses, turkey, seafood, seeds 5HT

30 receptor subtypes- many – at least 18 subtypes have been identified - probably best way to group 5HT1 and 5HT2 families; - some are metabotropic; some ionotropic 5HT

31 reuptake main mechanism for terminating – SSRIs breakdown – major metabolite 5HIAA 5HT

32 pervasive throughout the brain classified into 2 general categories – excitatory (glutamate, aspartate) – inhibitory (GABA, glycine) amino acids are more difficult to classify as nt amino acid neurotransmitters

33 first identified in leg of lobster causes hyperpolarization of neurons highest concentrations in brain and spinal cord and virtually absent in peripheral nerve or other organs does not cross bbb easily GABA

34 stored in synaptic vesicles (like other nt) usually removed from synapse via transporter (GAT) GABA also found in glia receptor subtypes: – GABA A – ionotropic – clinically important – GABA B - metabotropic GABA

35 mediates anxiolytic, sedative, anticonvulsant, muscle-relaxant and amnesic activity subunit compositions appear to vary from one brain region to another and even between neurons within a given region linked to chloride channel GABA A

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37 modulatory effects

38 found in high concentrations in brain serves many functions GAD (enzyme – can convert glutamate to GABA) glutamate

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40 found in high concentrations in brain serves many functions GAD (enzyme – can convert glutamate to GABA) receptor subtypes: – tremendous work done in recent years glutamate

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42 receptor subtypes: – NMDA, ionotropic, various other receptors including metabotropic GLU R (mGLUR) – families within these – role of neuromodulators current potential interests – reducing neurotoxicity, psychiatric disorders, substance use disorders, Alzhemiers Disease? glutamate

43 memantine 2005 – first non AChE inhibitor for treating AD Only approved for advanced (not early stage) uncompetitive low-to-moderate affinity NMDA receptor antagonist Multiple other uses possible

44 – acts as a neurotransmitter; also released during immune response; also found in gut – antihistaminergic effects: drowsiness, dry mouth, dizziness, sleepiness, upset stomach, decreased coordination, fatigue, weight gain, dry mouth and throat, upset stomach, fluttery heartbeat, loss of appetite, hives, sleepiness, vision problems More about histamine

45 Overview of nervous system

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47 PNS - peripheral nervous system 2 components- autonomic and somatic 1. autonomic nervous system -“involuntary” - role in emotion and stress - controls smooth muscles, cardiac muscles and glands

48 1. Sympathetic NS “fight or flight” activated during emergencies, stress and/or arousal Autonomic NS has two components

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50 Maintain homeostasis, energy restoration – physiological changes: 2. Parasympathetic nervous system

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52 voluntary nervous system – sensory and motor nerves – connection between all motor nerves and muscle (NMJ – neuromuscular junction) are nicotinic ACh synapses 2 nd part of the PNS is the somatic nervous system

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54 CNS – Central Nervous System – brain, spinal cord PNS – Peripheral Nervous System – Somatic, autonomic 2 divisions of the nervous system

55 3 main divisions of brain – hindbrain; midbrain; forebrain brain

56 hindbrain Medulla

57 medulla – Contains part of the reticular formation – (nuclei involved in integration of information from senses, attention, arousal, and control of sleep and wakefulness)hindbrain

58 medulla – Contains part of the reticular formation – (nuclei involved in integration of information from senses, attention, arousal, and control of sleep and wakefulness) as well as – Nuclei important for vital functionshindbrain

59 medulla – Contains part of the reticular formation – (nuclei involved in integration of information from senses, attention, arousal, and control of sleep and wakefulness) as well as – Nuclei important for vital functions – Various ascending and descending pathwayshindbrain

60 medulla hindbrain

61 pons – Contains part of the reticular formation Nuclei important for sleep and arousalhindbrain

62 pons – Contains part of the reticular formation Nuclei important for sleep and arousal – Specific nuclei include Raphe (5HT) – sleep and dreaming Locus coerulus (NE) - arousalhindbrain

63 pons – Contains part of the reticular formation Nuclei important for sleep and arousal – Specific nuclei include Raphe (5HT) – sleep and dreaming Locus coerulus (NE) - arousal Cerebellumhindbrain

64 Sensory information – reticular formation movement – substantia nigra - midbrain

65 cortical and subcortical structures forebrain

66 frontal parietal temporal occipital

67 4 lobes of cerebral cortex Frontal – Motor function – Prefrontal – higher “executive function”

68 4 lobes of cerebral cortex Frontal – Motor function Prefrontal – higher “executive function” Parietal – Somatosensory function Temporal – Audition – emotion Occipital – vision

69 Prefrontal cortex

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72 thalamus Some subcortical structures

73 The thalamus communicates with much of the cerebral cortex - serving as a sensory and motor information relay.

74 thalamus hypothalamus Some subcortical structures

75 thalamus hypothalamus limbic system Some subcortical structures

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77 thalamus hypothalamus limbic system basal ganglia Some subcortical structures

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79 S ome major nt pathways

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82 Mesolimbic/cortical – – Involved in reward, possible role in schizophrenia Projects to nucleus accumbens and parts of the limbic system nigrostriatal – – Important in initiation of movement; system that degenerates in Parkinsons disease projections from the substantia nigra to the basal ganglia tuberofundibular – – Important for hormonal release via hypothalamus and pituitary gland 3 major DA fiber tracts

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85 Peptides Opioids – Mu – Delta – Kappa – Endorphins and enkephalins are opioids Substance P Neurotransmitters and Receptors


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