HISTAMINE AND THE CAMP PATHWAY IN THE GUINEA-PIG PANCREAS

This study investigates the interaction between histamine and the aden ylate cyclase systems involved in the secretion of amylase from the gu inea-pig pancreatic lobules. Histamine increased amylase release, reac hing a maximum response at 10(-5) M. Similarly, vasoactive intestinal peptide (VIP) evoked significant increase in amylase release, though n ot in a dose-dependent fashion. When the pancreatic lobules were incub ated with histamine in combination with VIP, forskolin or 3-isobutyl-1 -methylxanthine (IBMX), amylase secretion was increased as compared to histamine alone. The stimulatory effect of VIP was also increased by the presence of forskolin or IBMX. These findings suggest that in guin ea-pig pancreatic lobules, VIP, forskolin and IBMX, agents involved in the cyclic adenosine monophosphate (cAMP) pathway, potentiate histami ne stimulated amylase release.