Pathogenesis of Tetanus

Overview

• Discussion on the pathogenesis of tetanus and the mechanism of tetanus toxin.
• Importance of inhibitory neurons in the nervous system.

Inhibitory Neurons

• Neurons that act like traffic signals in the nervous system.
• Secrete inhibitory neurotransmitters like:
  • Gamma-aminobutyric acid (GABA)
  • Glycine
• Ensure smooth functioning of the nervous system.

Tetanus Toxin (Tetanusplasmin)

• Extremely potent toxin.
• Taken up by the neuromuscular junction (motor end plate).
• Transported to the central nervous system.
  • Path of transport: Retrograde neural flow or blood.

Mechanism of Action

• Toxin acts on the inhibitory range of interneurons.
• Prevents the release of GABA and glycine.
• Inhibition of inhibitory interneurons results in:
  • Motor neurons sending high frequency impulses to muscle cells.
  • Sustained tetanic contraction.

Important Notes

• Tetanus toxin acts presynaptically at inhibitory neuron terminals.
• Different from strychnine poisoning, which acts postsynaptically.
• Critical point: The retrograde transport of the toxin is important for exams.

Conclusion

• Understanding the pathogenesis and mechanism is crucial for exams and medical practice.