Related Experiment Videos
Contractility of human gallbladder muscle in vitro
T M Feeley1, A S Clanachan, G W Scott
1Department of Pharmacology, University of Alberta, Edmonton, Canada.
Alimentary Pharmacology & Therapeutics
|December 1, 1987
Summary
Human gallbladder contractility is influenced by acetylcholine and peptides like CCK-OP, but not all hormones. Nerve stimulation causes contractions, with some inhibitory responses blocked by specific drugs, differing from animal models.
Area of Science:
- Gastroenterology
- Pharmacology
- Physiology
Background:
- Gallbladder contractility is crucial for bile release.
- Understanding neural and hormonal regulation is key to treating gallbladder dysfunction.
- Previous studies often used animal models, potentially limiting human relevance.
Purpose of the Study:
- To investigate the in vitro effects of neural and hormonal stimuli on human gallbladder contractility.
- To compare responses in gallbladders with varying degrees of chronic cholecystitis.
- To identify key neurotransmitters, hormones, and peptides influencing gallbladder muscle tone.
Main Methods:
- Isolated human gallbladder strips were used for in vitro contractility assays.
- Concentration-response curves were generated for acetylcholine and various agonists.
- The effects of transmural nerve stimulation and specific peptide hormones were assessed.
- Pharmacological antagonists were employed to elucidate receptor pathways.
Main Results:
- Acetylcholine induced concentration-dependent contractions, with similar sensitivity in mild and severe chronic cholecystitis.
- Noradrenaline and adrenaline caused relaxation, likely via beta 2-adrenoceptor stimulation.
- Transmural nerve stimulation evoked contractions, with atropine-sensitive inhibitory components blocked by propranolol.
- Peptides including cholecystokinin octapeptide (CCK-OP), gastrin, pentagastrin, substance P, and caerulein stimulated contractions, with some responses antagonized by dibutyryl cyclic GMP.
- Several hormones (motilin, secretin, VIP, etc.) had no significant effect.
Conclusions:
- Human gallbladder contractility is modulated by acetylcholine, certain peptides, and adrenergic pathways.
- Neural control involves cholinergic and beta-adrenergic mechanisms, with no evidence of non-adrenergic inhibitory responses.
- Significant species-specific differences exist in the direct neural and hormonal regulation of gallbladder contractility compared to animal models.