Chapter 5: Catecholamines

What are catecholamines?

A type of monoamine transmitter synthesized from tyrosine

What are the 3 major catecholamines?

Dopamine(DA), Norepinephrine (NE), and epinephrine (EPI)

What is the function of EPI and NE?

They play a role in fight or flight scenarios by increasing heart rate, blood pressure and energy

What is the rate limiting enzyme?

Tyrosine Hydroxylase

What does Tyrosine Hydroxylase do?

Converts tyrosine to neurotransmitters

What is Tyrosine?

A non-essential amino acid precursor for dopamine

How is dopamine synthesized?

Tyrosine is converted into L-DOPA and L-DOPA is decarboxylated to form dopamine

Where are the dopamine rich areas?

Hypothalamus, Olfactory Bulb, and Retina

Dopamine Functions (some)

Movement

Attention

Arousal

Memory

Sleep regulation

What is Dopamine?

A monoamine neurotransmitter and catecholamine

How are catecholamines stored and released?

They are stored in synaptic vesicles by vesicular monoamine transporters (VMAT) and released when the neuron fires

What’s the function of Reserpine

A blocking agent that prevents catecholamines from binding to storage vesicles

Function of amphetamines and methamphetamines

Causes the release catecholamines (DA & NE) without nerve firing

Effect of amphetamines and methamphetamines

Causes heightened alertness, euphoria, and hyperactivity

How are catecholamines removed from the synapse?

Through the reuptake by dopamine and norepinephrine transporters or recycled by glial cells and postsynaptic cells

What’s the function of MAO and COMT?

enzymes that break down catecholamines

How do D2 receptors differ from D1 receptors

D2 has a higher affinity and plays a role in inhibitory control and psychiatric disorders while D1 receptors are involved in movement and cognition