[Structural basis of neurohormonal control of gastric secretory activity]

Distances between neural, endocrinal and working cells in the gastric wall tissue do not exceed some hundreds nm, i. e. they are within limits of the physiological parameters for the effect of biologically active substances diffusely spreading along the interstitium. A structural scheme of the neurohormonal regulatory mechanism is suggested, basing on the author's data and those of the literature. Combination of producer-mediator-cells and target-cells united by the interstitial gap, along which biologically active substances are transported, serves as its base. Mast cells--mobile endocrinic glands--and neural terminals of various modality may serve as a source for changing the modulatory tonus in the given tissue area. The cells producing mediators (neural and endocrine) are, in their turn, target-cells for other biologically active substances getting into the interstitium. The whole structure can be compared with the synaptic system, where the membranes of the producer-mediator-cells serve as the presynaptic pole, while the membranes of the target-cells play the role of the postsynaptic pole. The interstitial gap performes the part of the synaptic gap. In this peculiar diffuse synapse, the membranes of neural and endocrine cells serve as pre- and postsynaptic membranes simultaneously.