RETENTION OF NERVE-TERMINALS IN DISPERSED PAROTID ACINAR-CELLS

The effects of veratridine, an agent known to increase Na permeability in excitable tissues, were determined on a dispersed cell preparation from the rat parotid gland. The uptake of 22Na by these parotid cells was increased in the presence of veratridine but not to as great an extent as with carbachol. The veratridine effect was blocked by both tetrodotoxin (TTX) and a combination of receptor blockers, atropine and phentolamine. TTX had no effect on the increase in 22Na uptake due to carbachol. Electron microscopic examination revealed the presence of nerve terminals in the dispersed cell preparation, often in very close apposition to individual cells. It is likely that these nerve terminals are the primary sites of actions of veratridine and TTX and not the parotid acinar cells. The possibility of the presence of unmyelinated nerve fibers should be taken into account in the analyses of experimental data obtained with dispersed cell preparations. © 1979.