Which among the following statements is TRUE about presynaptic inhibition?
Presynaptic inhibition provides a mechanism for controlling the efficacy of transmission at individual synapses. It is mediated by axo axonal synapses. Binding of neurotransmitters to the receptors mediating presynaptic inhibition leads to a reduction in the amount of neurotransmitter secreted by the postsynaptic axon. This reduction is caused either by a decrease in the size of the action potential in the presynaptic terminal as a result of activation of K+ or Cl- channels or by reduced opening of Ca2+ channels in the presynaptic terminal, thereby decreasing the amount of transmitter release. Presynaptic inhibition thus provides a mechanism whereby the "gain" at a paicular synaptic input to a neuron can be reduced without reducing the efficacy of other synapses that impinge on that neuron. Ref: Waxman S.G. (2010). Chapter 3. Signaling in the Nervous System. In S.G. Waxman (Ed), Clinical Neuroanatomy, 26e.
It results due to failure of the action potential to reach the synapse
It occurs due to hyperpolarization of presynaptic membrane
It occurs due to inhibition of release of neurotransmitter from presynaptic terminal
It occurs due to blockade of neurotransmitter receptors