Morphine is μ-opioid receptor (MOR) agonist that is used clinically for patients suffering from moderate to severe pain. Morphine can cause constipation due to activation of μ-opioid receptors in the central nervous system and the nervous system in the gastrointestinal tract. It is caused by increasing the expression of AQP-3 in the instestine through increased of serotonin by enterochromaffin cells. PEG 4000 is one of the osmotic laxatives used to treat Opioid Induced Constipation (OIC). PEG 4000 affects the upregulation of serotonin re-uptake which can lead to expression enhancement of AQP-3. The purpose of this study was to analyze the effect of PEG 4000 on expression changes of aquaporin-3 in mice colon induced acute constipation with morphine.Constipation conditions and the effectiveness of laxative therapy are indicated by constipation parameters in the form of fecal water content and stool weight. This study used 36 male mice of the Balb/c line genus which were divided into 3 groups, normal saline, morphine, and morphine + PEG 4000. Each group was further divided into 2 subgroups based on the time of observation, namely the first hour and fifth hour after morphine induced. The expression of AQP-3 was observed using Polymerase Chain Reaction (PCR) method. The result of this study showed that the administration of PEG 4000 to mice induced constipation with morfine could decrease the expression of AQP-3 from (146,413±1,736) to (118,411±3,476) with p value <0,05, increase the percentage of fecal water content from (0,000±0,000%) to (28,903±12,930%) with p value <0,05 and increase the stool weight from (0,000±0,000g) to (0,928±0,178g) with p value <0,01 From these results, it can be concluded that the administration of PEG 4000 in morphine induced constipation to mice was effective in reducing AQP-3 expression as well as increasing the percentage of fecal water content and stool weight.
