[Capillary networks and osmotic uptake in fungiform papillae]

In the research it has been tested the ability of convoluted capillary network of the fungiform papillae to act as countercurrent ionic exchanger and therefore to give rise a water uptake from the external environment. Manometric determinations of the water inflow during immersion of the tongue in solutions of different osmolality have shown a conspicuous water uptake, osmotic in nature and largely supported by the Na+ absorbed from the external solutions. The Na+ inhibits also the receptor electrical response to the stimulating Ca++ solutions. These observations show that the papillae can be considered as osmotic devices and emphasise also that the Na+ is directly involved in the papillary functional activity.