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Amrinone action on guinea-pig isolated stomach fundus
Archives Internationales De Pharmacodynamie Et De Therapie
|January 1, 1987
Summary
Amrinone causes transient contractions in guinea-pig stomach fundus via cholinergic receptors. Its primary effect is concentration-dependent relaxation, mediated by endogenous adenosine and requiring calcium influx.
Area of Science:
- Pharmacology
- Gastroenterology
Background:
- Amrinone is a phosphodiesterase inhibitor.
- Its effects on gastrointestinal smooth muscle are not fully understood.
Purpose of the Study:
- To investigate the effects of amrinone on guinea-pig stomach fundus strips.
- To elucidate the mechanisms underlying amrinone-induced contractions and relaxations.
Main Methods:
- Organ bath studies using guinea-pig stomach fundus strips.
- Dose-response experiments with amrinone.
- Pharmacological interventions including receptor antagonists, enzyme inhibitors, and altered ion concentrations.
Main Results:
- Amrinone induced transient, concentration-independent contractions mediated by cholinergic receptors.
- Amrinone caused pronounced, concentration-dependent relaxation.
- Relaxation was potentiated by dipyridamole and inhibited by adenosine deaminase, reduced Ca2+ concentration, and verapamil.
- Cholinergic receptor activation was implicated in contractions, while adenosine and Ca2+ influx were crucial for relaxation.
Conclusions:
- Amrinone's effects on stomach fundus involve both cholinergic activation and endogenous adenosine pathways.
- The relaxing effect of amrinone is dependent on extracellular calcium influx.