Chapter 4. Psychopharmacology. Copyright Allyn & Bacon 2004

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1 Chapter 4 Psychopharmacology This multimedia product and its contents are protected under copyright law. The following are prohibited by law: any public performance or display, including transmission of any image over a network, preparation of any derivative work, including the extraction, in whole or in part, of any images; any rental, lease or lending of the program. 1

2 Psychopharmacology Psychopharmacology: The study of the effects of drugs on the nervous system and on behavior. Drug effects: The changes a drug produces in an animal s physiological processes and behavior. Sites of Action: The locations at which molecules of drugs interact with molecules located on or in cells of the body, thus affecting some biochemical processes of these cells. 2

3 Principles of Psychopharmacology Pharmacokinetics Pharmacokinetics: The process by which drugs are absorbed, distributed within the body, metabolized, and excreted. 3

4 Principles of Pharmacology Routes of Administration Intravenous (IV) injection: Injection of a substance directly into a vein. Intraperitoneal (IP) injection: The Injection of a substance into the peritoneal cavity-the space that surrounds the stomach, intestines, liver, and other abdominal organs. 4

5 Principles of Pharmacology Routes of Administration Intramuscular (IM) injection: Injection of a substance into a muscle. Subcutaneous (SC) injection: Injection of a substance into the space beneath the skin. Oral administration: Administration of a substance into the mouth, so it is swallowed. 5

6 Principles of Pharmacology Routes of Administration Sublingual administration: Administration of a substance by placing it beneath the tongue. Intrarectal administration: Administration of a substance into the rectum. Inhalation: Administration of a vaporous substance into the lungs. 6

7 Principles of Pharmacology Routes of Administration Topical administration: Administration of a substance by placing it directly onto the skin or mucous membrane Intracerebral administration: Administration of a substance directly into the brain. Intracerebroventricular (ICV) administration: Administration of a substance into one of the cerebral ventricles. 7

8 Principles of Pharmacology Drug Effectiveness Dose-response curve: A graph of the magnitude of an effect of a drug as a function of the amount of the drug administered. Therapeutic index: The ratio between the dose that produces the desired effect in 50% of the animals and the dose that produces toxic effects in 50% of the animals. 8

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11 Principles of Pharmacology Effects of Repeated Administration Tolerance: A decrease in the effectiveness of a drug that is administered repeatedly. Sensitization: An increase in the effectiveness of a drug that is administered repeatedly. 11

12 Principles of Pharmacology Effects of Repeated Administration Withdrawal symptom: The appearance of symptoms opposite to those produced by a drug when the drug is administered repeatedly and then suddenly no longer taken. 12

13 Principles of Pharmacology Placebo Effects Placebo: An inert substance given to an organism in lieu of a physiologically active drug; used experimentally to control for the effects of mere administration of a drug. 13

14 Sites of Drug Action Antagonist: A drug that opposes or inhibits the effects of a particular neurotransmitter on the postsynaptic cell. Agonist: A drug that facilitates the effects of a particular neurotransmitter on the postsynaptic cell. 14

15 Sites of Drug Action Effects on Receptors Direct agonist: A drug that binds with an activates a receptor. Receptor blocker: A drug that binds with a receptor but does not activate it; prevents the natural ligand from binding with the receptor. 15

16 Sites of Drug Action Effects on Receptors Direct antagonist: Synonym for a receptor blocker. Noncompetitive binding: Binding of a drug to a site on a receptor; does not interfere with the binding site for the principal ligand. 16

17 Sites of Drug Action Effects on Receptors Indirect antagonist: A drug that attaches to a binding site on a receptor and interferes with the action of the receptor; does not interfere with the binding of the principal ligand. Indirect agonist: A drug that attaches to a binding site on a receptor and facilitates the action of the receptor; does not interfere with the binding site of the principal ligand. 17

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20 Acetylcholine The first transmitter to be discovered. The primary neurotransmitter secreted by the efferent axons of the central nervous system. All muscular movement is accomplished by the release of acetylcholine. Appears to be involved in regulating REM sleep, perceptual learning, and memory. 20

21 Acetylcholine Botulinum toxin: An acetylcholine antagonist; prevents release by terminal buttons. Black widow spider venom A poison produced by the black widow spider that triggers the release of acetylcholine. Neostigmine: A drug that inhibits the activity of acetylcholinesterase. 21

22 Acetylcholine Nicotinic receptor: An ionotropic acetylcholine receptor that is stimulated by nicotine and blocked by curare. Muscarinic receptor: A metabotropic acetylcholine receptor that is stimulated by muscarine and blocked by atropine. Atropine: A drug that blocks muscarinic acetylcholine receptors. Curare: A drug that blocks nicotinic acetylcholine receptors. 22

23 Monoamines Catecholamines Dopamine (DA) Norepinephrine (NE) Epinephrine Indolamines Serotonin (5-HT) 23

24 Monoamines Monoamine: A class of amines that includes indolamines such as serotonin and catecholamines such as dopamine, norepinephrine, and epinephrine. Indolamines Serotonin (5-HT) 24

25 Monoamines Dopamine Dopamine: A neurotransmitter; one of the catecholamine. Produces both excitatory and inhibitory postsynaptic potentials. Implicated roles in movement, attention, learning, reinforcing effects of abused drugs. Synthesized from tyrosine that we obtain from our diet. 25

26 Monoamines Dopamine L-Dopa: The levorotatory form of DOPA; the precursor of the catecholamines; often used to treat Parkinson s disease because of its as a dopamine agonist. 26

27 Monoamines Dopamine Nigrostriatal system: A system of neurons originating in the substantia nigra and terminating in the neostriatum (caudate nucleus and putamen of the basal ganglia); appears to play a role in the control of movement. 27

28 Monoamines Dopamine Mesolimbic system: A system of dopaminergic neurons originating in the ventral tegmental area and terminating in the nucleus accumbens, amygdala, and hippocampus; appears to play a role in the reinforcing effects of drugs that are commonly abused. 28

29 Monoamines Dopamine Mesocortical system: A system of dopaminergic neurons originating in the ventral tegmental area and terminating in the prefrontal cortex; appears to influence formation of short-term memories, planning, and preparing strategies for problem solving. 29

30 Monoamines Dopamine Parkinson s Disease: A neurological disease characterized by tremors, rigidity of the limbs, poor balance, and difficulty in initiating movements; caused by degeneration of the nigrostriatal system; Parkinson s disease has been treated with L-DOPA. 30

31 Monoamines Dopamine AMPT: A drug that blocks the activity of tyrosine hydroxylase and thus interferes with the synthesis of the catecholamines. Reserpine: A drug that interferes with the storage of monoamines in synaptic vesicles; serves as a monoamine antagonist. 31

32 Monoamines Dopamine Apomorphine: A drug that blocks dopamine autoreceptors at low doses; at high doses blocks postsynaptic receptors as well. Methylphenidate: A drug that inhibits the reuptake of dopamine; also known as Ritalin ; used to treat children with attention deficit disorder. 32

33 Monoamines Dopamine Monoamine oxidase (MAO): A class of enzymes that destroy the monoamines; dopamine, norepinephrine, and serotonin. deprenyl: A drug that blocks the activity of MAO-B; acts as a dopamine agonist. 33

34 Monoamines Dopamine Chlorpromazine: A drug that reduces the symptoms of schizophrenia by blocking dopamine D 2 receptors. Clozapine: A drug that reduces the symptoms of schizophrenia, apparently by blocking dopamine D 4 receptors. 34

35 Monoamines Norepinephrine (NE) Norepinephrine is synonymous with noradrenaline. Found in neurons of the brain and the autonomic nervous system. Almost every region of the brain receives input from noradrenergic neurons. Implicated to play central role in vigilance or attentiveness to events in the environment. 35

36 Monoamines Norepinephrine (NE) Norepinephrine: One of the catecholamines; a neurotransmitter found in the brain and in the sympathetic division of the autonomic nervous system. Epinephrine: One of the catecholamies; a hormone secreted by the adrenal medulla; serves as a neurotransmitter in the brain. 36

37 Monoamines Norepinephrine (NE) Fusaric acid: A drug that inhibits the activity of the enzyme dopamine-ß-hydroxylase and thus blocks the production of norepinephrine. Locus coeruleus: A dark-colored group of noradreneric cell bodies located in the pons near the rostral end of the floor of the fourth ventricle. 37

38 Monoamines Serotonin (5-HT) Serotonin: Serotonin is an indolamine neurotransmitter; also called 5-hydroxytryptamine (5-HT); thought to play a role in the regulation of mood, the control of eating, sleep, dreaming, and arousal; also thought to be involved in the regulation of pain. 38

39 Monoamines Serotonin (5-HT) PCPA: A drug that inhibits the activity of tryptophan hydroxylase and thus interferes with the synthesis of 5-HT. 39

40 Monoamines Serotonin (5-HT) Fluoxetine (Prozac): A drug that inhibits the reuptake of 5-HT. 40

41 Monoamines Serotonin (5-HT) Fenfluramine: A drug that stimulates the release of 5-HT; used as an appetite suppressant. LSD: Lysergic acid diethylamide This drug produces distortions of visual perceptions. A drug that stimulates 5-HT 2a receptors. 41

42 Amino Acids The most common amino acid transmitters are: Glutamate Gamma-amino-butyric acid (GABA) Glycine 42

43 Amino Acids Glutamate Glutamate: An amino acid; the most important excitatory neurotransmitter in the brain. NMDA: A drug that serves as a noradrenergic and serotonergic agonist 43

44 Amino Acids Glutamate NMDA receptor: A specialized ionotropic glutamate receptor that controls a calcium channel that is normally blocked by Mg 2+ ions; has several other binding sites. AMPA receptor: An ionotropic glutamate receptor that controls a sodium channel; stimulated by AMPA and blocked by CNQX; the most common glutamate 44 receptor.

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46 Amino Acids Glutamate Kainate receptor: An ionotropic glutamate receptor that controls a sodium channel; stimulated by kainic acid and blocked by CNQX. Metabotropic glutamate receptor: A category of metabotropic receptors sensitive to glutamate. AP5: A drug that blocks the glutamate binding site on 46 NMDA receptors

47 Amino Acids Glutamate Phencyclidine (PCP): A drug that binds with the PCP binding site of the NMDA receptor and serves as an indirect antagonist of glutamate. Behavioral symptoms include altered body image, feelings of isolation and sadness, cognitive disorganization, apathy, hostility euphoria and dreamlike states. 47

48 Amino Acids GABA GABA: An amino acid; the most important inhibitory neurotransmitter in the brain and spinal cord. 48

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50 Amino Acids GABA Benzodiazepine: A category of anxiolytic drugs; an indirect agonist for the GABA A receptor. Anxiolytic: An anxiety-reducing effect. 50

51 Amino Acids Glycine Glycine: An amino acid; an important inhibitory neurotransmitter in the lower brain stem and spinal cord. Strychnine: A direct antagonist for the glycine receptor. 51

52 Peptides Neurons of the central nervous system release a large variety of peptides. A neuron manufactures both the polypeptides and the enzymes that it needs to break them apart. Synthesis takes place in the soma and they are delivered to the terminal buttons by axoplasmic transport. Most peptides appear to serve as neuromodulators, some act as neurotransmitter. 52

53 Peptides Endogenous opioid: A class of peptides secreted by the brain that act as opiates; drugs that effect opioid receptors reduce pain. Enkephalin: One of the endogenous opioids. Naloxone: A drug that blocks opioid receptors. 53

54 Lipids Cannabinoid: A lipid; an endogneous ligand for receptors that bind with THC, the active ingredient in marijuana. Anandamide: A lipid; the endogenous ligand for receptors that bind with THC, the active ingredient of marijuana. 54

55 Lipids Adenosine: A nucleoside; a combination of ribose and adenine; serves as a neuromodulator in the brain. Caffeine: A drug that blocks adenosine receptors. 55

56 Soluble Gases Nitric oxide (NO): A gas produced by cells in the nervous system; used as a means of communication between cells. 56

Classes of Neurotransmitters. Neurotransmitters

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