The role of μ-opioid receptor in gastrointestinal transit was investigated using μ-opioid receptor knockout mice (MOR-KO). Our result establishes unequivocally that inhibition of GI transit by morphine is a μ-opioid receptor mediated function. In addition, we show that neither S nor K receptor agonist given supraspinally or peripherally are able to inhibit GI transit in MOR-KO animals. It was interesting to observe that basal GI motility was lower in MOR-KO (-/-) compared to heterozygous (±) and wild type (+/+) animals.
Bibliographical noteFunding Information:
This work was supported by NIH grants DA00564, DA01583, DA05695, K05-DA70554, F. and A. Stark Fund (MMF)-HHL and DA08188 (SR).
- Gastrointestinal motility
- μ-Opioid receptor