1. Neurotransmitters: Monoamines
Lesson 9

2. CRITERIA 1. NT found in axon terminals
2. NT released by action potentials
3. Synthesis identified
4. External application mimic normal response
5. Pharmacology same for normal and externally applied NT
Mechanism of action
Actions of agonists & antagonists
Direct & indirect ~

3. Monoamines Amino acid precursors single amine group 2 groups
Catecholamines - catechol ring
Indolamine - indole ring
Affected by many of same drugs ~

4. Monoamines Catecholamines Dopamine - DA Norepinephrine - NE
Dopaminergic
Norepinephrine - NE
Noradrenergic: neurons
Adrenergic: drugs/receptors
Epinephrine - E
Adrenergic ~
Indolamine
Serotonin - 5HT
Serotonergic

5. Monoamines Terminated by... reuptake MAO - monoamine oxidase
COMT - catechol-O-methyltransferase
also in liver
Reserpine  blocks storage
initially stimulates NT release
profound depletion over several days ~

6. Indirect Monoamine Agonists
MAOI
monoamine oxidase inhibitors
Reuptake blockers
Tricyclic antidepressants
aka Non-selective reuptake inhibitors
Cocaine & Amphetamine ~

7. Monoamines
Reserpine
MAO A
COMT

8. Dopamine Only in central nervous system mostly inhibitory systems
all metabotropic
Reward
Schizophrenia
Movement
Nigrostriatal Pathway
At least 5 DA-R types: D1, D2, etc. ~

9. Dopaminergic Drugs Agonist L-DOPA Antagonists Chlorpromazine
Haloperidol
D ~

10. Dopamine Synthesis Tyrosine DOPA DA
hydroxylase
aromatic amino acid
decarboxylase
Tyrosine
DOPA DA
DOPA
decarboxylase
AADC (aromatic amino acid decarboxilase) is AKA DOPA decarboxilase ~

11. Norepinephrine Peripheral N.S. Sympathetic neuroeffector junction
Adrenal glands
Central N.S.
Hypothalamus
Locus coeruleus
a & b groups of receptor subtypes
metabotropic ~

12. Adrenergic Drugs Agonists Mescaline Ephedrine Clonidine Antagonist
Yohimbine (a2)
Propranalol (b-blocker) ~

13. Norepinephrine Synthesis
tyrosine
hydroxylase
dopamine
b hydroxylase
AADC
Tyrosine
DOPA DA NE

14. Serotonin NOT a catecholamine Peripheral 98% in blood & smooth muscle
Central N.S.
Raphe nucleus
Hypothalamus
R subtypes: 5HT1 , 5HT2 , etc. ~

15. Serotonergic Drugs Agonists SSRIs MDMA Ecstasy
Selective Serotonin Reuptake Inhibitors
MDMA
Ecstasy
neurotoxicity in rats & primates ~

16. Serotonergic Drugs Antagonists Psilocybin LSD Buspirone
autoreceptor agonist in CNS
Buspirone
5HT1a
Inverse agonist
ketanserin ~

17. Serotonin Synthesis 5-HT Tryptophan 5-HTP 5-HTP – 5 hydroxytryptophan
hydroxylase
AAADC
Tryptophan
5-HTP
5-HT
5-HTP – 5 hydroxytryptophan
5-HT – 5 hydroxytryptamine