Age-related decrease of cholinergic parasympathetic reflex vasodilation in the rat masseter muscle.

Skeletal muscle hemodynamics, including that in jaw muscles, is an important in their functions and is modulated by aging. Marked blood flow increases mediated by parasympathetic vasodilation may be important for blood flow in the masseter muscle (MBF); however, the relationship between parasympathetic vasodilation and aging is unclear. We examined the effect of aging on parasympathetic vasodilation evoked by trigeminal afferent inputs and their mechanisms by investigating the MBF during stimulation of the lingual nerve (LN) in young and old urethane-anesthetized and vago-sympathectomized rats.

Effect of the parasympathetic vasodilation on temperature regulation via trigeminal afferents in the orofacial area.

The skin temperature (T) of the orofacial area influences orofacial functions and is related to the blood flow (BF). Marked increases in BF mediated by parasympathetic vasodilation may be important for orofacial T regulation. Therefore, we examined the relationship between parasympathetic reflex vasodilation and orofacial T in anesthetized rats.

Relationship between impaired parasympathetic vasodilation and hyposalivation in parotid glands associated with type 2 diabetes mellitus.

We examined the relationship between hemodynamics in the three major salivary glands and salivary secretion in urethane-anesthetized and sympathectomized type 2 diabetic and nondiabetic rats via laser speckle imaging and by collecting the saliva. Lingual nerve stimulation elicited rapid increases in glandular blood flow and induced salivary secretion from the three glands in both diabetic and nondiabetic rats. In the parotid gland, the magnitude of blood flow increase and salivary secretion was significantly lower in the diabetic rats when compared with the nondiabetic rats; however, this was not observed in the other glands.