**1. Introduction**

If you are fortunate enough to grow in age and turn 100 years old, you are a centenarian. That is the term used for those human folks who are 100 years or older. The term is not typically applied to neurotransmitters. However, the neurotransmitter acetylcholine was discovered a little more than one hundred years ago, in 1921, by German-born scientist Otto Loewi. While human folks might face their final farewell at this age, current research on acetylcholine is testament to its young age, making it a young centenarian. As a PhD student in the Neuroscience program at the University of Arizona [https://neuroscience.arizona.edu/], my fellow students and I learned about acetylcholine as one of the major neurotransmitters in the nervous system, its synthesis, breakdown, and recycling [1, 2]. The fascinating story of acetylcholine's discovery and its functional importance for brain signaling upheld my continuous interest in this neurotransmitter.
