The present results help to shed some light on the understanding of the vasoactive mechanisms induced by cigarette smoking, and to support the hypothesis that cigarette smoking causes nervously mediated vasoconstriction in the healthy human gingiva. However, the degree of vasoconstriction was far less than in the thumb skin, and in our subjects was overcome by the evoked rise in arterial perfusion pressure. As a consequence, gingival blood flow increased during smoking. It is speculated that small repeated vasoconstrictive attacks due to cigarette smoking may in the long run contribute to gingival vascular dysfunction and periodontal disease.
Resting GBF of periodontitis patients was not lower in smokers than in non-smokers, but it was significantly lower than in the younger reference subjects. In contrast to our earlier findings in healthy subjects, smoking one cigarette may cause a decrease in GBF and VC in periodontitis patients. These observations suggested the existence of a dysfunction in the gingival vasculature in smokers and non-smokers with periodontitis.
Inhibitory effects of root filling materials on the conduction of action potentials evoked in rat phrenic nerves were evaluated in vitro. Endomethasone and N2 Normal completely and irreversibly inhibited conductance; ProcoSol caused complete but reversible inhibition; Kloroperka N-O caused total inhibition which was sometimes reversed; and AH26 and Diaket showed partial inhibition which was partially reversible.
Snuff-induced blood flow responses in the gingiva were evaluated in 22 healthy casual consumers of tobacco. Laser Doppler flowmetry (LDF) was used to measure blood flow simultaneously and continuously on two gingival sites (buccal aspect of the papillae between the upper lateral incisors and canines). In addition, measurements of skin blood flow in the forehead and palmar side of the left thumb were performed. Arterial blood pressure (BP) and heart rate (HR) were also recorded. Unilateral application of commercial snuff (500 mg, 1%) caused a marked and rapid increase in gingival blood flow (GBF) on the exposed side (p < 0.001). Blood flow increased also in the contralateral gingiva and forehead skin (p < 0.05). Skin blood flow in the thumb showed an insignificant decrease. BP and HR increased. Vascular conductance increased significantly in the snuff-exposed gingiva but not in the contralateral gingiva or the forehead. Vascular conductance was largely unaffected in the thumb. It is concluded that acute application of snuff, besides giving rise to typical changes in BP and HR, increases GBF in and around the exposed area, probably through activation of sensory nerves and the subsequent release of vasodilatory peptides from their peripheral endings. Blood flow in unexposed gingival and forehead skin may increase probably due to humoral or nervously mediated mechanisms. However, a passive pressure-induced hyperaemia in the unexposed gingiva and forehead skin can not be excluded.
AARs, H. Aortic baroreceptor activity in normal and hypertensive rabbits. Acta physiol. scand. 1968. 72. 298-309. The baroreceptor activity in the entire left aortic nerve was recorded in 9 normal and 5 hypertensive rabbits. A technique based on rectification and integration of the nerve potentials allowed separate analysis of the mean, systolic and diastolic activities. The nervous activities measured at different diastolic blood pressures showed only small variations during recordings over several hours, and small inter-individual variations. In hypertensive rabbits, the receptors required a higher pressure to start firing than in normal rabbits. The activity was lower at all pressures in hypertensive animals. The difference from normal rabbits increased with increasing pressure, and was most pronounced for the systolic part of the firing. Mechanisms for causing the resetting of baroreceptor activity in hypertension are discussed. It is concluded that a combination of hypertensive wall changes and exhaustion or destruction of some receptors is probably responsible for the resetting.
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