Because only NHE3 has been found to traffic between the plasma membrane and the recycling endosomes and tends to acidify the early endosomes and perhaps secretory granules59, elevation of NHE3 mRNA might contribute to increase transmitter(s) release, for example, GDNF, Substance P and/or ATP, in GERD patients. This evidence concerns the gene GDNF and gastroesophageal reflux disease.