Answer
Tetanus bacteria festers in wounds and produce the toxin tetanospasmin. This toxin gets into lymph and the vascular system from intercellular spaces . At neuromuscular junctions the tetanus toxin binds to membrane of motor neurons ad sis transmitted inn a retrograde manner along motor neurons into the central nervous system -- the spinal cord and the brain stem. In the spinal cord the toxin crosses trans-synptically into inhibitory interneurons. . In the inhibitory neuron one unit of the toxin acts as a peptidase that cleaves synaptobrevin a protein necessary for release of inhibitory neurotransmitters ( GABA and glycine) from the presynaptic vesicles of the interneurons Because the inhbitory neurotransmitters cannot be released by vesicular exocytosis, the moto neurons respond to almost all sensorystimui that impact them. The increased excitabilty of muscles in a group agonists and antagonis results in spastic contraction .
Work Step by Step
Tetanus toxin tetanospasmin travels in a retrograde manner back along the axons of motor neurons to the central nervous. There they cross trans-synaptically into inhibitory motor neurons and act to inhibit the release of glycine and GABA inhibitory neurotransmitters.
