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Studies on neurotensin. I. Effects on gallbladder motility
Nihon Geka Hokan. Archiv Fur Japanische Chirurgie
|September 1, 1989
Summary
Neurotensin (NT) stimulates gallbladder contraction in dogs through cholinergic pathways, as demonstrated in vivo. However, NT was ineffective on isolated rabbit gallbladder muscle in vitro, unlike cholecystokinin-octapeptide (CCK-8).
Area of Science:
- Gastroenterology
- Pharmacology
- Physiology
Background:
- Neurotensin (NT) is a peptide with known physiological effects.
- The role of NT in gallbladder motility requires further elucidation.
- Cholecystokinin-octapeptide (CCK-8) is a primary stimulant of gallbladder contraction.
Purpose of the Study:
- To investigate the effects of neurotensin (NT) on gallbladder contraction.
- To compare the action of NT with cholecystokinin-octapeptide (CCK-8) on the gallbladder.
- To determine the pathways involved in NT-induced gallbladder contraction.
Main Methods:
- In vivo studies utilized strain-gauge force transducers on dog gallbladders to measure contraction.
- In vitro studies examined longitudinal rabbit gallbladder muscle strips.
- Neurotensin (NT) and cholecystokinin-octapeptide (CCK-8) were administered intravenously and in vitro.
Main Results:
- In vivo, NT induced gallbladder contraction at doses of 20 and 40 ng/kg (bolus) and 250 and 500 ng/kg/hr (infusion).
- NT-induced contraction was transient and abolished by atropine, indicating cholinergic involvement.
- In vitro, NT was ineffective on rabbit gallbladder muscle, while CCK-8 caused dose-dependent contraction.
Conclusions:
- Neurotensin (NT) stimulates gallbladder contraction in dogs via cholinergic pathways.
- The ineffectiveness of NT in vitro suggests species-specific or indirect mechanisms.
- NT's action differs from CCK-8, which acts directly and dose-dependently on gallbladder muscle.