Brief Summary: This early phase I trial studies the guanylyl cyclase C (GCC) agonist effect on cGMP signal in duodenal tissue. Plecanatide and linaclotide are drugs approved by the Food and Drug Administration for the treatment of conditions related to constipation. This trial aims to see the effects of taking either one of two drugs, plecanatide or linaclotide, or no drug, on a certain chemical found in the tissue collected from small intestine and how they compare.

Detailed Description: PRIMARY OBJECTIVE: I. To assess and compare participants randomly assigned 1:1:1 to one of three intervention arms (plecanatide 3 mg versus linaclotide 145 mcg versus no active agent) with respect to change in cyclic guanosine monophosphate (cGMP) accumulation in normal appearing duodenal mucosa specimens. SECONDARY OBJECTIVES: I. Characterization and comparison of the following outcomes (in prioritized order): Ia. cGMP levels in luminal fluid from participants receiving either linaclotide or plecanatide to fluid from participants receiving no agent; Ib. Vasodilator stimulated phosphoprotein (VASP) phosphorylation in normal-appearing duodenal mucosa biopsy specimens from participants receiving either linaclotide or plecanatide to those specimens from participants receiving no agent. EXPLORATORY OBJECTIVES: I. Comparison of cGMP and VASP phosphorylation between the plecanatide and linaclotide arms. II. Transcriptome analysis of cellular response (ribonucleic acid \[RNA\] sequencing analyses) to define whether GCC ligand exposure induces reproducible changes in duodenal messenger \[m\]RNA expression that can serve as a reliable biomarker of GCC-cGMP signaling in future studies. OUTLINE: Patients are randomized to 1 of 3 arms. ARM I: Patients receive a single dose of plecanatide (3 mg) orally (PO) 60-120 minutes prior to standard of care esophagogastroduodenoscopy (EGD) with biopsy and luminal fluid collection. Patients also undergo biopsy on study. ARM II: Patients receive a single dose of linaclotide (145 mcg) PO 60-120 minutes prior to standard of care EGD with biopsy and luminal fluid collection. Patients also undergo biopsy on study. ARM III: Patients undergo standard of care EGD with biopsy and luminal fluid collection. Patients also undergo biopsy on study. After completion of study intervention, patients are followed up at day 7.