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Adenosine: a novel ulcer modulator in stomachs
1Department of Pharmacology, Faculty of Medicine, University of Hong Kong.
Acta Physiologica Hungarica
|January 1, 1992
Summary
Adenosine protects against ethanol-induced gastric lesions by increasing blood flow. However, its antiulcer effects are complex, potentially involving different adenosine receptor subtypes.
Area of Science:
- Gastroenterology
- Pharmacology
Background:
- Adenosine influences gastric secretion and stress-induced ulcers.
- Gastric mucosal blood flow (GMBF) is closely linked to gastric lesion formation.
Purpose of the Study:
- To investigate adenosine's effects on ethanol-induced gastric lesions and GMBF in rats.
- To determine if adenosine's actions involve adenosine A1 or A2 receptors.
Main Methods:
- Administered adenosine, L-phenylisopropyladenosine (L-PIA), and N-ethylcarboxamidoadenosine (NECA) to rats.
- Measured GMBF and assessed ethanol-induced gastric lesion formation.
- Investigated the roles of adenosine A1 and A2 receptors using specific agonists.
Main Results:
- Adenosine (7.5 mg/kg) pretreatment increased GMBF and protected against gastric lesions.
- This protective effect was followed by aggravated lesions and reduced GMBF.
- L-PIA and NECA dose-dependently inhibited GMBF and potentiated gastric damage.
- Combined L-PIA and NECA did not worsen ulceration or reduce GMBF further.
Conclusions:
- Adenosine's initial antiulcer action is not mediated by A1 or A2 receptors.
- The later aggravation of lesions and reduced GMBF by adenosine may involve A1 and A2 receptors.
- Adenosine likely acts through different receptor subtypes to produce its biphasic effects on gastric protection and damage.