Histaminergic modulation of hormonal control in the exocrine guineapig pancreas

Abstract

The effects of histamine upon secretin- or cholecystokinin (CCK)-evoked exocrine pancreatic secretion were investigated in the anaesthetised guinea pig. Histamine (0.1 mumol/kg/min) induced a slight increase in pancreatic juice flow and total protein release compared to saline controls. Secretin (0.5 pmol/kg/min) and CCK-8 (0.75 pmol/kg/min) evoked marked time course increases in both the rate of pancreatic juice flow and total protein output in the anaesthetised guinea pig. Administration of either secretin or CCK-8 simultaneously with histamine elevated the exocrine pancreatic secretion compared to the smaller response obtained when administered separately. These results indicate that histamine may play an important physiological role in modulating the hormonal control of exocrine guinea pig pancreas.

The physiological role of histamine in the exocrine pancreas

“…These results suggest that the paracrine hormone may play an important physiological role in modulating the hormonal control of exocrine pancreatic secretion. The failure of histamine to potentiate CCK-8-evoked protein output corroborates the evidence that it is acting on the exocrine pancreas as a secretin-like hormone to increase pancreatic fluid secretion compared to protein output [73]. Histamine in the pancreas is likely derived from mast cells located in the gland [22,23].…”

“…However, when histamine was infused simultaneously with either secretin or CCK-8 there was a marked potentiation in both flow and protein output in the presence of secretin and only a potentiation in flow with CCK-8. Histamine failed to enhance the CCK-8-evoked protein output [73]. These results suggest that the paracrine hormone may play an important physiological role in modulating the hormonal control of exocrine pancreatic secretion.…”

Regulation of Pancreatic Secretion

“…232 H1 receptors are coupled to inositol phosphate metabolism and generation of intracellular calcium as an intracellular signal. 237 This finding suggests that histamine potentiates CCK-stimulated effects similar to those of secretin and may signal through a common intracellular mediator such as cAMP. 233 H3 receptors are located on presynaptic nerve terminals and inhibit the release of neurotransmitters.…”