Assessment of diarrhea or constipation
The animals were kept in metabolic cages two days before they were killed. They
were left to adapt for one day and then the feces were collected the second day. The feces were weighed and dried in an oven at 100C for 3 h and weighed again. The water content was calculated using the following formula:
Radioimmunoassays (RIA)
The tissue specimens were allowed to thaw and then weighed. The peptides were extracted by boiling the tissue in 3 ml 0.5 M acetic acid, followed by homogenization and centrifugation for 20 min at 700 xg. The supernatant was neutralized with 1 M NaOH and stored at –70C until the time for assay. Somatostatin, substance P, vasoactive intestinal peptide (VIP) and galanin were determined in all gastrointesti-