An investigation into the relationship between small intestinal fluid secretion and systemic arterial blood pressure in the anesthetized rat.

The effects of changes in the steady level of diastolic blood pressure on fluid flux across the jejunum has been investigated in the anesthetized rat during perfusion with a nutrient-free and Na(+)-free solution. Diastolic blood pressure was manipulated by intravenous infusions, during the jejunal perfusions, of vasodilators (vasoactive intestinal polypeptide, acetyl-β-methylcholine, and phentolamine) and a vasoconstrictor (arginine vasopressin), each of which acts through a different cellular mechanism. The outcome was that fluid flux was related by a parabolic relationship with diastolic blood pressure in which net secretion occurred over the range 40-100 mmHg, whereas net absorption was recorded at diastolic pressures exceeding 100 mmHg and below 40 mmHg.

Prolonged stimulation of pancreatic serous secretions by bile and sodium taurocholate in anaesthetized rats.

There have been numerous reports that infusion of either natural bile or bile salts into the duodenum evokes a rapid increase in pancreatic secretion through the release of the hormone secretin from the duodenal mucosa. We have extended this observation by the demonstration of an additional late increase in secretion which persisted for many hours and have sought to identify the processes underlying this increase. In anaesthetised rats, infusion of 20 mM taurocholate into the duodenum caused a staircase-like increase in the weight of pancreatic secretion which extended over many hours during which, the HCO[Formula: see text] and protein output of the secretion showed only minimal changes.