INTERACTION BETWEEN PAIN AND VASODILATION INTHE PULPITIS, IDENTIFICATION OF VASODILATOR SUBSTANCES

(1)组胺是一种经典但仍然有趣的炎症介质。长期以来，许多人认为组胺仅来自肥大细胞或嗜碱性粒细胞。然而，隐藏胺形成酶，组氨酸脱羧酶(HDC)，在各种组织中被诱导，对革兰氏阳性和革兰氏阴性细菌成分和各种细胞因子做出反应。即使在肥大细胞缺陷的小鼠中也能诱导HDC。通过诱导HDC新形成的组胺会立即释放，并可能参与多种免疫反应。我们得出结论，组胺可以通过与细胞因子网络耦合的机制诱导HDC产生。我们称这种组胺为新组胺，以区别于来自肥大细胞或嗜碱性粒细胞的经典组胺。新组胺参与生理反应、炎症反应、免疫反应和牙髓炎等多种疾病。(2)通过电刺激Ian远端不同水平的基线血流量(BBF)，诱导猫下颌尖牙髓血流量(PBF)的动态变化，并用激光多普勒血流仪监测血流量。PBF血管扩张剂反应的幅度随着BBF的降低而增加(通过降温牙齿)。相反，PBF血管收缩反应的幅度随着BBF水平的升高而增加。通过改变BBF水平，血管扩张剂反应可转化为血管收缩反应，反之亦然。在整个实验过程中，没有引起全身血压的变化。这些结果表明，当我们讨论或计算PBF对各种刺激的反应大小时，考虑基线血管张力是重要的。

(1) Histamine is a classical, but still interesting inflammatory mediator. Many people have long believed that histamine is derived from mast cells or basophils alone. However, the hidtamine forming enzyme, histidine decarboxylase (HDC), is induced in a variety of tissues in responses to gram-positive and gram-negative bacterial components and to various cytokines. HDC is induced even in mast-cell-deficient mice. The histamine newly formed via the induction of HDC is released immediately and may be involved in a variety of immune responses. We conclude that histamine can be produced via the induction of HDC by a mechanism coupled with cytokine network. We call this histamine neohistamine to distinguish it from the classical histamine derived from mast cells or basophils. Neohistamine is involved in physiological reactions, inflammation, immune responses and a variety of diseases such as pulpitis.(2) Dynamic changes in pulpal blood flow (PBF) in cat mandibular canine teeth were elicited by electrical stimulation of the distal cut end of IAN, at various levels of baseline blood flow (BBF), with blood flow monitored by Laser Doppler Flowmetry. The amplitude of the PBF vasodilator response increased as BBF was adjusted downwards (by cooling down the tooth). In contrast, the amplitude of the PBF vasoconstrictor response increased as the BBF level rose. Vasodilator responses could be transformed into vasoconstrictor responses, and vice versa, by alterations in the BBF level. No systemic blood pressure changes were elicited throughout the experiment. These results indicate that a consideration of baseline vascular tone is important whenever we discuss or calculate the size of PBF responses to various stimuli.