Final answer:
Tetanus toxin, produced by Clostridium tetani, blocks the release of inhibitory neurotransmitters like glycine and GABA, leading to sustained muscle contractions and severe symptoms such as lockjaw.
Step-by-step explanation:
The toxin that blocks the release of inhibitory neurotransmitters such as glycine and GABA (gamma-aminobutyric acid) is known as tetanus toxin, produced by Clostridium tetani. This neurotoxin consists of two subunits: a light A subunit and a heavy chain B subunit. Tetanus toxin specifically targets inhibitory interneurons at the neuromuscular junction, which regulate the release of glycine and GABA. These neurotransmitters are essential for the inhibition of acetylcholine release, thereby controlling muscle contractions. By inhibiting glycine and GABA release, the tetanus toxin causes sustained muscle contractions, leading to symptoms such as lockjaw and eventually, can lead to respiratory failure and death.
Botulinum toxin (Botox), produced by Clostridium botulinum, acts in a similar way but causes flaccid paralysis instead by preventing the release of acetylcholine. GABAergic neurotransmission is a crucial aspect of brain function, with GABA acting as the primary inhibitory neurotransmitter, and glycine playing a similar role in the spinal cord and brainstem. The release of these neurotransmitters is generally mediated via synaptic vesicles, and they exert their effects through specific receptors, contributing to the regulation of neuronal excitability.