This paper employs MEMS force sensors to explore the role of mechanical tension in neuro transmission. Here, the nervous system of Drosophila (fruit fly) embryo is examined. The accumulation of vesicles that carry neuro transmitter at the synapse between the axons and muscle tissue is measured using florescent technique. The tensile force on axons are measured in vivo. The rest tension in axons is found to be about 1 nN. Increasing the tension by mechanical probing results in increasing vesicle accumulation. The results suggests that nature employs mechanical tension as a means of tuning neuro transmission efficiency, and hence memory formation.