Homeostasis in the gastric mucosa and blood circulation. Part 1. Mechanisms of the adequate blood flow maintenance in the gastric mucosa]

The increase of mucosal blood flow in response to food entrance into stomach or different irritant action is the component of gastric mucosal defence barrier. Sufficient blood flow ensures normal acid-bicarbonate balance in gastric mucosa, supports the healing process and prevents superficial damages from developing into deep ones. Capsaicin-sensitive afferent nerve fibers play the large role in the blood flow regulation. The influence of these nerve fibers on the gastric blood flow is mediated by the calcitonin-gene related peptide. This peptide released from peripheral afferent terminals improves microcirculation in stomach walls. Moreover nerve impulses from afferent neurons modulate parasympathetic activity that in turn induces the increase of gastric mucosal blood flow through both choilinergic and noncholinergic mechanisms. The gastric mucosal blood flow may be also regulated by humoral and paracrine metabolites. Nitric oxide and prostaglandines are the most important low molecular weight compounds. They play the main role in the maintenance of the basal gastric mucosal blood flow and in the development of hyperemic responses to harmful agents.