Peripheral pathways mediating salivary secretion after nucleus parvocellularis activation in the rat

The present study demonstrates that activation of the nucleus parvocellularis in the pontine reticular formation of the rat evokes salivary hypersecretion. The secretory effect observed was found to be mediated by parasympathetic mechanisms, as transection of the preganglionic parasympathetic salivatory fibers at the level of the middle ear blocked the flow of saliva evoked by activation of the nucleus parvocellularis (Experiment 1). Furthermore, transection of these salivatory fibers was followed several days later by the development of a prandial model of drinking. These behavioral data suggest that the transection procedure employed in the present study indeed affected those parasympathetic fibers which control the secretory activity of all three pairs of major salivary glands (Experiment 2).