Search

Sympathetic regulation of periodontal ligament blood flow (PLBF) is well-attested; however, vasodilator responses mediated by parasympathetic nerve fibers have yet to be conclusively demonstrated in the periodontal ligament (PL). The present study was designed to determine whether parasympathetic vasodilator mechanisms do or do not exist in the cat PL. In our cats, the cervical sympathetic trunks were sectioned bilaterally prior to any stimulation in order to eliminate sympathetic effects on the vascular beds under study. Dynamic changes in PLBF, with mandibular lip blood flow (LBF) recorded for comparison, were investigated in cat mandibular canine teeth using laser Doppler flowmetry. The peripheral cut ends of the facial and glossopharyngeal nerve roots, which have been reported to contain parasympathetic nerve fibers to the oral tissues, were electrically stimulated intracranially. Such stimulation caused blood flow to increase in the ipsilateral PL and lip, without an increase in systemic blood pressure. These vasodilator responses in the PL and lip were sensitive to ganglion blockade (with hexamethonium), indicating vasodilatation via activation of parasympathetic vasodilator fibers. In contrast, although intracranial stimulation of the trigeminal nerve root also induced increases in both PLBF and LBF, these were unaffected hexamethonium, but reduced by tripelennamine, indicating antidromic vasodilatation via the trigeminal sensory nerve. These results suggest that parasympathetic vasodilator mechanisms do exist in feline PL. [ABSTRACT FROM AUTHOR]

The purpose of the study was to calibrate the laser Doppler signals with simultaneous measurements made by the H2 gas clearance method in the cat gingiva. Four young adult cats were used, weighing from 2.5 to 4.8 kg for the study. The GBF values measured and those measured by the H2 gas clearance were plotted. The results suggest that stimulation of the ipsilateral cervical sympathetic trunk for 5 mm induced a stable and long-lasting decrease in gingival blood flow (GBF) during stimulation.

This article focuses on a study on the acute response of periodontal ligament blood flow to external force application. For this study ten adult cats were used, each weighing from 2.4 to 4.5 kg. They were anesthetized with an i.m. injection of ketamine hydrochloride, 35 mg/kg initially, and then with an i.v. injection of Nembutal 35 mg/kg, supplemented when necessary with additional doses of 5 mg/kg. The trachea was cannulated, and the blood pressure in the femoral artery was monitored continuously by means of a pressure transducer, and recorded on a polygraph. The animal's head and jaws were fixed by a steel rod secured to the jaws by dental acrylic.