Neurotransmitters:Catecholamines & Acetylcholine

Chapters 5 & 6

Catecholamines

Dopamine

Norepinephrine

Epinephrine

Acetylcholine

Serotonin

Glutamate

GABA

Neurotransmitters

Neurotransmitter Families

Structural features of catecholamines

Synthesis of Catecholamines

“rate-limiting enzyme”

CatecholeminesSome adjectives

• Dopamine (DA)– “dopaminergic”

• Norepinephrine (NE)– “noradrenergic”

• Epinephrine (EPI)– “adrenergic”

Storage of Catecholaminesvesicular monoamine transporter protein (VMAT2)

Behavioral effects of reserpine

http://home.caregroup.org/clinical/altmed/interactions/Images/Herbs/rauwolfi.gif

Dopamine Systems in the Brain

• Mesolimbic pathway– Reinforcement

• Mesocortical pathway– Planning

• Nigrostriatal pathway– Movement

Symptoms of Parkinson’s Disease

• Difficulty moving• Tremor in resting body parts• Loss of balance, frequent falls• Cognitive dysfunctions in memory, abstract

thinking, language• Premature death

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Damage to the substantia nigra

http://www.urmc.rochester.edu/neuroslides/slides/slide199.jpg

Causes of Parkinson’s Disease

• Degeneration of substantia nigra• Less dopaminergic activity in basal ganglia• Discovery of MPPP MPTP and MPP+

A typical dopaminergic neuron

D1 and D2 receptors

Catalepsy can be produced by D2 receptor antagonists

Norepinephrine

http://homepage.psy.utexas.edu/homepage/class/Psy301/Salinas/sec2/Brain/31.GIF

Role of the locus coeruleus in vigilance

Synthesis of acetylcholine (ACh)

Functions of Acetylcholine (ACh)

• Neuromuscular junction (movement)

• Central nervous system (learning and memory)

cholinergic synapse

Acetylcholine Receptors

• Nicotinic receptors– Neuromuscular junctions– Ionotropic (ion channel)– Curare works on these receptors

• Muscarinic receptors– Metatropic (second messengers)– Hippocampus, striatum

• Morphine– Also located in heart and smooth

muscles• Nightshade

Cholinergic synapses in the parasympathetic and sympathetic

branches of the ANS