Carbachol potentiates the cyclic AMP-stimulating effect of VIP in cat submandibular gland

The effect of VIP and carbachol on cyclic AMP production were studied in isolated acini of the cat submandibular gland and guinea pig pancreas. VIP was almost 100 times more potent in stimulating cyclic AMP in the pancreas than in the submandibular salivary gland. Carbachol did not influence cyclic AMP in the pancreas while a 20-30% increase was seen in the submandibular gland. The addition of carbachol potentiated the cyclic AMP response to VIP in the submandibular acini while no such effect was observed in the pancreas. Atropine abolished the effect of carbachol.