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”

Catecholemines Some adjectives Dopamine (DA) – “dopaminergic” Norepinephrine (NE) – “noradrenergic” Epinephrine (EPI) – “adrenergic”

Storage of Catecholamines vesicular monoamine transporter protein (VMAT2)

Behavioral effects of reserpine

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

Damage to the substantia nigra

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

D 1 and D 2 receptors

Catalepsy can be produced by D 2 receptor antagonists

Norepinephrine

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