Microbiology General 48d21353 Mechanism of action of tetanospasmin A Inhibition of GABA release B Inhibition cAMP C Inactivation of Ach receptors D Inhibition of cGMP High-Yield Explanation Ans. is 'a' i.e., Inhibition of GABA release . Tetanospasmin blocks the release of inhibitory neurotransmitters (GABA and glycine) in brain-stem and spinal cord.