The Effect of Histamine, H₁ and H₂ Agonists, and H₁ and H₂ Antagonists on Postprandial Pancreatic Polypeptide Release in Dogs

Abstract

The influence of histamine, H₁ and H₂ agonists (2-AETD and dimaprit), and H₁ and H₂ antagonists (mepyramine and Cimetidine) on the postprandial release of pancreatic polypeptide (PP) was assessed in five Labrador retrievers. Infusions of histamine, 0.25 μmol kg⁻¹h⁻¹; 2AETD, 4 μmol kg⁻¹h⁻¹; and dimaprit, 1 μmol kg⁻¹h⁻¹, enhanced postprandial release (131-189% of control values). The response to 2-AETD and dimaprit was significantly different from control values (p < 0.05). An increase was observed even when 50 mg mepyramine and 400 mg Cimetidine were injected as intravenous boluses (131-139% of control values (p < 0.05)). The action of the antagonists may be explained by partial agonism or histamine release induced by these agents. It is concluded that postprandial PP release is stimulated by H₁ and H₂ receptors.

Key-words:

• Aminoethyl thiazole
• Cimetidine
• dimaprit
• histamine
• H₁ agonist
• H₂ agonist
• H₁ antagonist
• H₂ antagonist
• mepyramine
• pancreatic polypeptide