Segments of intestine from patients undergoing elective gastric bypass for morbid obesity or resections for non-obstructive neoplasms at the UC Davis Medical Center will be used. Samples will be taken from tissue normally removed and sent to Pathology or discarded. Full thickness segments of intestine (10 mm x 1 mm) will be prepared for recording either intracellular electrical activity or mechanical contraction. The effects of putative non-adrenergic, non-cholinergic neurotransmitters (e.g., nitric oxide) will be studied. The source of the tissue will not be identified either directly or indirectly through identifiers associated with the measured responses.
