Download What are examples of common agonists and antogonists?

Psychology 304:
Brain and Behaviour
Lecture 15
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Neuropharmacology
1. What neurotransmitters have been identified?
(continued)
2. How do drugs affect the conduction and transmission
of electrochemical neural signals?
3. What are examples of common agonists and
antogonists?
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What neurotransmitters have been identified?
(continued)
• Large-molecule neurotransmitters are neuropeptides:
 Found largely in neurons of the CNS.
 Include five categories: pituitary peptides,
hypothalamic peptides, brain-gut peptides, opioid
peptides, and miscellaneous peptides.
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 The function of each neuropeptide depends upon its
amino acid sequence.
 Associated with analgesia, reinforcement, feeding,
learning, and memory.
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How do drugs affect the conduction and transmission
of electrochemical neural signals?
• Drugs: Exogenous chemicals that are not necessary for
normal functioning and significantly alter cellular
functioning when taken in relatively low doses.
• May be introduced into the central nervous system
through diverse means.
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• Drugs may be classified as agonists or antagonists.
• Agonists facilitate the effects of neurotransmitters.
Antagonists inhibit the effects of neurotransmitters.
• Agonists and antagonists may influence synaptic
transmission in a number of ways:
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Mechanisms of Agonist and Antagonist Drug Effects
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What are examples of common agonists and
antogonists?
• Examples of common drugs that act as agonists are:
 L-DOPA: Serves as a precursor for dopamine.
 Alcohol: Stimulates the release of dopamine;
stimulates postsynaptic receptors for GABA.
 Cannabis: Stimulates the release of dopamine.
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 Phencyclidine (PCP): Stimulates the release of
dopamine.
 Ecstasy (MDMA): Stimulates release of serotonin.
 Caffeine: Blocks autoreceptors for dopamine.
 Nicotine: Stimulates postsynaptic receptors for
acetylcholine.
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Effects of Ecstasy on Serotonin Neurons
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Non-Users of
Ecstasy
Users of
Ecstasy
Effects of Ecstasy: Non-Users vs Users.
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 Tranquilizers (i.e., benzodiazepines; e.g.,
Valium): Stimulate postsynaptic receptors for GABA.
 Tricyclic antidepressants: Block reuptake of
serotonin and norephinephrine.
 SSRI antidepressants: Block reuptake of serotonin.
 St. John’s Wort: Blocks reuptake of serotonin;
inhibits enzymes that break down monoamines (e.g.,
serotonin).
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 Cocaine: Blocks reuptake of dopamine.
 Amphetamine: Stimulates release of dopamine and
norephinephrine, blocks the reuptake of dopamine
and norepinephrine.
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Coca-Cola Ads
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Coca Wine Ad
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Ad for Cocaine-Based Toothache Drops
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Rotting of Teeth due to Metamphetamine Abuse
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Physical Impact of Metamphetamine Abuse
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Neuropharmacology
1. What neurotransmitters have been identified?
(continued)
2. How do drugs affect the conduction and transmission
of electrochemical neural signals?
3. What are examples of common agonists and
antogonists?
19