ACETYLCHOLINE AND GLUTAMATE

Name two diseases associated with acetylcholine and glutamate dysregulation.

Myasthenia Gravis and Alzheimer’s Disease.

What are two critical functions of acetylcholine?

Muscle contractions and regulation of memory and sleep.

How is acetylcholine synthesised?

From choline and acetyl-CoA via the enzyme choline acetyltransferase.

What enzyme breaks down acetylcholine?

Acetylcholinesterase.

What type of receptors does acetylcholine bind to, and what are their general properties?

Nicotinic Receptors: Ionotropic, facilitate ion flow.

Muscarinic Receptors: Metabotropic, activate G-proteins.

What are the subtypes of muscarinic receptors?

M1 to M5.

What is Myasthenia Gravis?

It is an autoimmune disease where antibodies attack nicotinic receptors at the neuromuscular junction.

What is the treatment for Myasthenia Gravis?

Cholinesterase inhibitors to increase acetylcholine at synapses.

How does Botox affect acetylcholine?

It inhibits acetylcholine release, causing temporary muscle paralysis.

What is atropine, and what is its effect?

Atropine is a muscarinic receptor antagonist used for pupil dilation.

What is glutamate's primary role in the central nervous system?

It is the primary excitatory neurotransmitter.

How is glutamate synthesized?

From glutamine via the enzyme glutaminase.

What are the three types of ionotropic glutamate receptors?

NMDA, AMPA, and Kainate receptors.

What is a key feature of NMDA receptor activation?

It requires magnesium removal and co-agonists to activate.

What are metabotropic glutamate receptors (mGluRs)?

G-protein coupled receptors that modulate neuronal excitability and synaptic plasticity.

How does glutamate dysregulation contribute to Alzheimer’s Disease?

It causes excitotoxicity, leading to neurodegeneration.

What drug is used in advanced Alzheimer’s stages, and how does it work?

Memantine, an NMDA receptor antagonist.

What role does glutamate play in synaptic plasticity?

NMDA receptor subunits regulate changes in synaptic strength essential for learning and memory.

What is ketamine’s mechanism of action?

It is an NMDA receptor antagonist used as an anesthetic and antidepressant.

How is acetylcholine recycled after release?

It is broken down into choline and acetate by acetylcholinesterase, with choline recycled for reuse.

How is glutamate recycled in the synaptic cleft?

It is taken up by astrocytes, converted to glutamine, and returned to neurons.

What determines the physiological response of nicotinic and NMDA receptors?

Their subunit composition.

What makes acetylcholine and glutamate essential in the nervous system?

Their roles in motor control, cognition, and synaptic transmission

Why is continued research on acetylcholine and glutamate important?

To develop better treatments for neurological diseases as current drugs manage symptoms but are not curative.