Do Acid Sensing Ion Channels Contribute to Heartburn?

Inclusion Criteria: * Adults, 18-59 years old * moderate heartburn at least 3 days/week * males and non-pregnant/non-lactating females * Complete relief while using a PPI or only some relief of symptoms while on a PPI Exclusion Criteria: * erosive esophagitis * unable or unwilling to undergo endoscopy and biopsy or Bernstein testing * eosinophilic esophagitis * negative Bernstein test * known hypersensitivity to amiloride * renal disease * diabetes * hypotension * electrolyte imbalance * contraindication to diuretics, including taking lithium or ACE inhibitors. -history of gastric or esophageal surgery * history of ZE syndrome * bleeding disorder * UGI bleeding * esophageal motor disorder * esophageal stricture * Barrett's esophagus * UGI malignancy * esophageal varices * subjects with current malabsorption * inflammatory bowel disease * severe heart-lung-liver-renal-cerebrovascular disease * subjects post-transplant * diabetes * actively taking the following medications: tricyclic antidepressants, quinidine, quinine, dilantin, warfarin, narcotic analgesics, antineoplastic agents, salicylates (except a baby aspirin for cardiovascular protection); steroids, NSAIDs (including COX-2 inhibitors), KCl, anti-tuberculosis medication, bisphosphonates, and triamterene, cyclosporine, tacrolimus, and other potassium sparing drugs like spironolactone * serum potassium of 5.5 mEq/L or higher