Disclosed is a composition including: an isolated in vitro pre-conditioned population of adult bone marrow derived mesenchymal stem cells (BMSCs), wherein the BMSCs express neuronal markers, and wherein the neuronal markers are PGP9.5, NSE, Tuj1, HuC/D and neuronal nitric oxide synthase (nNOS). Methods of preparing the BMSCs are also provided. In addition, the present disclosure is directed to a method of treating an enteric nervous system-related disorder including: administering to a subject in need thereof a pharmaceutical composition including the in vitro pre-conditioned BMSC population and a pharmaceutically acceptable carrier.