Synaptic conduction is mostly ohodromic because:

D i.e. Chemical mediator is located only in the presynaptic terminaOhodromic conduction means conduction in one direction only, from one neuron called the presynaptic neuron to another neuron called the postsynaptic neuronQ.Transmission at synapse is always in one direction only because the neurotransmitter substance responsible for conduction is present in vesicles of presynaptic neurons onlyQ. The post synaptic neuron does not contain any neurotransmitterQ. It has protein molecules embedded in it which serve as receptor for the neurotransmitter.Electrical synapses can transmit signals in either direction.Q