1. ) Dopamine 2. ) Norepinephrine 3. ) Epinephrine

1. ) Serotonin (5-HT) 2. ) Melatonin

Catechol-O-methyltransferase - methylates hydroxyl group (ring) - POST-synaptic membrane + cytosol - primarily extracellular

Adrenergics Flashcards by Steve Lane

Inhibitor: Tyrosine Hydroxylase

Catalyzes Tyrosine –> DOPA metabolism
RATE-LIMITING STEP

Metyrosine

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Inhibitor: VMAT

Blocks H+/dopamine countertransport
Vesicular Monoamine Transporter (VMAT)

Reserpine

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Inhibitor: Vesicle release

Inhibits VAMP/SNAP interaction + NE/ATP/P release

Bretylium
Guanethidine

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Inhibitor: NET

Norepinephrine Transporter (NET)

Cocaine,
Tricyclic Antidepressants (TCAs)

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Chatecholamines (3)

) Dopamine
) Norepinephrine
) Epinephrine

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Indolamines (2)

) Serotonin (5-HT)

2. ) Melatonin

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Reserpine

Inhibitor of VMAT transport
-depletes secretory vesicles of NTs
-prevents release into synapses
S/Sx: MAJOR depressive disorder (“no joy”)

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MAO (MOA + 2 Classes)

Monoamine Oxidase
-converts amine --> acid (inactivates)
-associated with mitochondria (intracellular)
MAO-A --> 5-HT + NE
MAO-B --> dopamine (DA)

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COMT

Catechol-O-methyltransferase

methylates hydroxyl group (ring)
POST-synaptic membrane + cytosol
primarily extracellular**

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Alpha-1 Receptors

Vascular SM

Fx: vasoconstriction

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Alpha-2 Receptors

Brain
Fx: lowers blood pressure

“reduce sympathetic output”

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Beta-1 Receptors

Heart

Fx: increased contraction force, increase HR

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Beta-2 Receptors

Bronchial SM + Vascular SM

Fx: Dilation (both areas)

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Beta-3 Receptors

Adipose tissue
Fx: lipolysis

VERY RARE

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Beta-Adrenergic Receptors: GCPR Effect

Increase/stimulate Adenylate Cyclase (AC)

Increased [cAMP]

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Alpha-Adrenergic Receptors: Adenylate Cyclase (AC)

Decreased/inhibits Adenylate Cyclase (AC)

Decreased [cAMP]

Uses of Adrenergic Agonists

Cardiovascular (Shock, anaphylaxis, HTN)
Respiratory (COPD, asthma)
Ophthalmic (glaucoma, dilation)
CNS (ADHD, narcolepsy, pain, depression)

NorEpi Therapy Problems (4)

) Non-selective (a1, a2, b1, b2)
) Rapid metabolism (COMT + MAO)
) Poor oral bioavailability
) Does not cross BBB

NorEpi Alterations: Amino Substitution

Increases b-receptor affinity

-prevents MAO-A metabolism (blocks amino group)

NorEpi Alteration: OH modification

Inhibits COMT-metabolism

increases oral bioavailability
increased duration of action
increases BBB penetration/permeability

Epinephrine (modifications, receptor affinity)

Methyl group added to NorEpi NH2 (blocks MAO)

a1 = a2 = b1 ≈ b2

Isoproterenol (modifications, receptor affinity)

Isopropyl group conjugated to NorEpi NH2
b1 = b2&raquo_space;»»>a1/2

Affinity to b receptors increases as group conjugated to amine increases in size (CH3 vs. CH(CH3)2)

Adrenergic Agonist Effects: a1

a1 –> peripheral blood vessel SM (vasoconstriction)
Increased BP, peripheral resistance

Non-CV: decongestant, pupil dilation (phenylephrine)
NO EFFECT ON ACCOMMODATION

Adrenergic Agonist Effects: a2

a2 –> post-synaptic receptors brain
Reduced sympathetic outflow, decreased BP

Non-CV: decongestant, glaucoma (brimonidine)

Adrenergic Agonist Effects: b1

b1 --> heart/cardiac myocytes increased HR, contractile force, increased BP Non-CV: INCREASE aqueous humor secretion

Adrenergic Agonist Effects: b2

b2 --> bronchiole + vascular SM (dilation) Vasodilation, decreased BP, decreased peripheral resistance Non-CV: Bronchodilation (terbutaline)

Timolol

Julie's procedure - Non-selective (b1 + b2) - Increases aqueous humor production, but DECREASES amount going into eye (decreases pressure) - non-specific therefore some off-target effects (if in circulation)

Betaxolol

b-1 selective glaucoma agent

Tx: ADHD (3)

1. ) Amphetamine 2. ) Methylphenidate 3. ) Atomoxetine (reuptake inhibitor)

Tx: Appetite Suppression (3)

1. ) Amphetamine 2. ) Methamphetamine 3. ) Phentermine

Narcolepsy Tx

Modafinil - inhibits DA reputake - increases NE, 5-HT, orexin, histamine, glutamate (indirectly) - decreases GABA transmission

Psychostimulants: ADEs

Cardiovascular (tachy, HTN, CAs) CNS (hyper, anxiety, HA, weight loss) GI (N/V, urinary retention) Addiction