The study aims to determine the expression of the ionotropic glutamate receptors in colon of irritable bowel syndrome (IBS) patients and evaluate the relationship between the ionotropic glutamate receptors and IBS symptoms.

Ionotropic glutamate receptors participate in pain in nervous system. In this study,participants will examine the expression of the ionotropic glutamate receptors in colon of irritable bowel syndrome (IBS) patients and evaluate the relationship between the ionotropic glutamate receptors and IBS symptoms.

Participants may futher study the mechanism using cell experiment.

Inclusion Criteria:

Patients meeting IBS Rome III criteria. Asymptomatic individuals for health surveillance or patients for follow up after polypectomy.

Exclusion Criteria:

Patients with known cancers or abdominal surgery. Alarm symptoms such as anaemia, gastrointestinal bleeding or obstruction, marked weight loss, abdominal mass. Patients who are unwilling to sign or give the informed consent form. Patients with impaired cardiac, liver or renal function. Patients with coagulopathy. Patients with pregnancy or breastfeeding.

Patients underwent colonoscopy in Qilu Hospital outpatient and inpatient department.