Abstract
The role of peripheral and central opioid receptors in morphine-induced migrating myoelectric complexes (MMECs) was studied in conscious dogs implanted with silver-silver chloride electrodes. In normal fasted dogs morphine (100-200 μg/kg iv) initiated phase III of the MMEC in the duodenum. Once initiated the MMEC propagated distally. This effect of morphine was blocked by the opioid receptor antagonists naloxone (2 mg/kg iv) and N,N-diallylnormorphinium bromide (4 mg/kg iv). Higher doses of morphine (300-600 μg/kg iv) initiated phase III activity in fed dogs as early as 20 min after feeding, while lower doses (150 μg/kg iv) initiated phase III activity routinely when administered 100 min after feeding. In dogs with bilateral vagotomies and bilateral thoracolumbar sympathetic chain ganglionectomies, morphine (150 μg/kg iv) initiated phase III activity in the duodenum, which then migrated distally. This study demonstrates that morphine initiates phase III of the MMEC by acting through peripheral opioid receptors.
Original language | English (US) |
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Pages (from-to) | G557-G562 |
Journal | American Journal of Physiology - Gastrointestinal and Liver Physiology |
Volume | 12 |
Issue number | 5 |
DOIs | |
State | Published - Jan 1 1985 |
ASJC Scopus subject areas
- Physiology
- Hepatology
- Gastroenterology
- Physiology (medical)