NEUROTOXINS:

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NEUROTOXINS BOTULISM, SARIN GAS NOVOCAINE, AND
LIDOCAINE
VINKUL ROPERIA PHYSIOLOGY 3
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Clostridium Bacterium

• Clostridium bacteria are gram-positive rod-shaped
  bacteria that form spores that allow the bacteria
  to survive in a dormant state until exposed to
  conditions that can support growth.
• There are seven types of botulism neurotoxin
  designated by the letters A through G. Only types
  A, B, E, and F cause illness in humans.
• The Clostridium bacteria are considered to be
  anaerobic, which means these organisms grow best
  in low or absent oxygen levels.

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• Botulism is a rare but serious paralytic illness
  caused by a nerve toxin that is produced by the
  bacterium Clostridium botulinum.
• It is a serious illness that causes
  flaccid paralysis of muscles.

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Symptoms

• The classic symptoms of botulism include
• Double vision
• Blurred vision
• Drooping eyelids
• Slurred speech
• Difficulty swallowing
• Dry mouth
• Muscle weakness
• Constipation may occur.
• The doctor's examination may reveal that the gag
  reflex and the deep tendon reflexes like the
  knee-jerk reflex are decreased or absent.

• Infants with botulism appear lethargic, weak, and
  floppy, feed poorly, become constipated, and have
  a weak cry and poor muscle tone. In infants,
  constipation is often the first symptom to occur.
• These are all symptoms of the muscle paralysis
  that is caused by the bacterial neurotoxin

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• There are three main kinds of botulism
• 1. Foodborne botulism
• 2. Wound botulism
• 3. Infant botulism

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How does it work

• The neurotoxin actually paralyzes the nerves so
  that the muscles cannot contract.
• This happens when the neurotoxin enters the nerve
  cells and eventually interferes with the release
  of acetylcholine.

• Unless the nerve can regenerate a new axon that
  has no exposure to the neurotoxin, the
  interference at the neuromuscular junction is
  permanent.

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SARIN GAS
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• It has been classified as a weapon of mass
  destruction in the UN Resolution 687.
• It is a colorless, odorless liquid and it is used
  as a chemical weapon owing to its extreme potency
  as a nerve agent.

• Sarin gas is a human-made chemical warfare agent
  classified as a nerve agent.
• Sarin gas , or GB, is an organophosphorus
  compound.
• Organophosphorus compounds are degradable organic
  compounds containing carbonphosphorus bonds,
  used primarily in pest control as an alternative
  to chlorinated hydrocarbons that persist in the
  environment.

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• Like other nerve agents, sarin gas attacks
  the nervous system by stopping nerve endings at
  the muscles from switching off.
• Death will usually occur as a result
  of asphyxia due to the inability to control the
  muscles involved in breathing function.

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• Specifically, sarin gas is a potent inhibitor of
  acetylcholinesterase.
• Acetylcholine is the neurotransmitter used at
  the neuromuscular junction.

• Normally, acetylcholine is released from the
  neuron to stimulate the muscle, after which it is
  degraded by acetylcholinesterase, allowing the
  muscle to relax.

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NOVOCAINE
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• Owing to the ubiquity of the trade name Novocain,
  in some regions procaine is referred to
  generically as novocaine.
• Procaine is a local anesthetic drug of the amino
  ester group.
• It is used primarily to reduce the pain of
  intramuscular injection of penicillin, and it is
  also used in dentistry.

• It acts mainly by being a sodium channel blocker.

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• Local anesthetics like novocaine (procaine) are
  agents that prevent transmission of nerve
  impulses without causing unconsciousness.
• They act by binding to fast sodium channels from
  within (in an open state).

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• In dentistry it works by producing a trigeminal
  nerve conduction block, in the mandibular (3rd)
  branch, decreasing the permeability of the axon
  cell membrane to (Na) sodium ions.
• This mechanism prevents the entry of Na ions
  into the axon to propagate an action potential in
  both slow and fast pain fibers.

• Unmyelinated axons are the first to be affected.
• Myelinated motor nerves are only affected at the
  nodes of Ranvier.

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LIDOCAINE
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• Lidocaine is a common local anesthetic and
  antiarrhythmic drug.
• Lidocaine is usually used to relieve itching,
  burning and pain from skin inflammations.
• It is also injected as a dental anesthetic or as
  a local anesthetic for minor surgery.

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• Lidocaine works by temporarily blocking this
  pathway of pain signals along nerves.
• It does this by stopping the sodium entering the
  nerve ending at the site of the pain. This
  prevents an electrical signal building up and
  passing along the nerve fibers to the brain.

• Lidocaine is a type of medicine called a local
  anesthetic.
• It is used to numb areas that would otherwise
  feel pain.
• The stimulation causes sodium to enter the nerve.

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THE END