Bruce Pettipas

1
Acetylcholine

• By
• Bruce Pettipas
• Crystal Crosby
• Sara Kennedy
• Wade Swazey

2
Outline

• Introduction
• The Function of Acetylcholine in the Brain
• Mimics of Acetylcholine
• Diseases Associated with Acetylcholine

3
Introduction

• Discovered in 1921 by an Austrian scientist
• Major neurotransmitter in the peripheral nervous
  system
• Produced by the neurons in the parietal lobes of
  the brain
• Associated with thought, memory, and muscular
  coordination
• Associated with the speed of information
  processing in the brain and the production of
  myelin sheath

4
Introduction

• Chemical structure
• CH3                             O
•                                             
• H3CNCH2 CH2OC CH3
•            
•           CH3

5
Acetylcholine in the brain

• Acetylcholine (ACh) first isolated around 1914.
• In 1921 the functional significance of ACh was
  established by the German physiologist Otto
  Loewi. 
• ACh is composed of an ester of choline and acetic
  acid.
• The neurotransmitter ACh is stored in vesicles in
  the nerve endings.                                
                    
• When a nerve impulse arrives at a nerve ending,
  ACh is released and it binds with receptors on
  muscle cells to make them contract or relax.

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Acetylcholine in the brain

• ACh is responsible for motor control at the
  junction between nerves and muscles.
• It is the receptor that determines whether or not
  the muscle cell is stimulated or inhibited.
• ACh may either stimulate skeletal muscles or
  decrease heart rate.
• In addition to having affect on motor control,
  ACh influences mental processes such as learning,
  memory, sleeping, and dreaming.

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Mimics of Acetylcholine

• Mecholyl-A drug that mimics at ACh muscarinic
  receptor sites
• Carbachol- A mimic of ACh that isnt inactivated
  by Acetylcholinesterase
• Muscarine- a drug which is derived from the
  mushroom Amanita muscaria it mimics ACh in the
  parasympathetic and central nervous systems

8
Mimics of Acetylcholine

• Curare- a toxin used in the arrows of South
  American natives which binds to ACh receptor
  sites. This causes paralysis by interfering with
  transmition of nerve impulses. Muscles with more
  nerves tend to be affected first.
• Curare is also used in small amounts as
  anesthetic for abdominal surgery.
• Nicotine- A mimic of ACh. Current research shows
  that nicotine may be helpful to treat
  neurodegenerative disorders.

9
Diseases Associated with ACh

• Alzheimers Disease- the most common form of
  dementia that is associated with acetylcholine.
• It was first discovered in 1906 by Alois
  Alzheimer.
• It is a progressive, degenerative and
  irreversible neurological disease with no cure.
• AD tends to run in families due to certain genes.
• Symptoms can be seen as early as the age of 40,
  but are more frequent around the age 65.

10
Diseases Associated with ACh

• The following symptoms are often associated with
  the disease frequent memory loss, impaired
  thinking, impaired behavior, and difficulty in
  grasping or in expressing thought.
• In early stages of AD, Ach producing cells in the
  basal forebrain are damaged.
• The most striking symptom of AD is the loss of
  memory. This is due to decline in neurons in the
  cortex.

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Diseases Associated with ACh

• It is believed that most acetylcholine is in the
  neocortex which originates in the basal
  forebrain, that cholinergic synapses themselves
  were the sites for memory storage.
• The deposit of beta-amyloid peptides in the brain
  in the form of senile plaque is primarily
  responsible for Alzheimer pathology which may be
  indirectly toxic to neurons by activating micro
  glial cells.

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Diseases Associated with ACh

• Butulinism- prevents the release of acetylcholine
  in the body
• This can paralyze the repertory muscles, causing
  suffocation and/or death.
• Other diseases that have been associated with
  acetylcholine are bipolar disorder, mood swings
  and depression.