Refulation of PAF biosynthesis and its role in salivary secretion

血小板激活因子（PAP）由多种炎症和免疫相关细胞释放。此外，PAF的产生已在更广泛的细胞和组织中得到证实，并表明PAF发挥着多种生理和病理作用。我们之前已经证明，PAF 是在狗唾液腺细胞受到生理刺激时产生的。本研究检查了 PAP 生物合成的调节及其在唾液腺分泌反应中的作用。1 乙酰胆碱 (ACh)、苯肾上腺素、异丙肾上腺素和 8Br-环 AMP 增加了溶血-PAP：乙酰辅酶 A 乙酰转移酶 (ACT) 和 DDT 不敏感磷酸胆碱转移酶。 ACh 和去氧肾上腺素以 Ca^2^ 依赖性方式增加 ACT 和 PAP 生成。2 通过使用 RT-PCR 技术检查 PAF 受体基因表达来研究唾液腺中的 PAP 受体表达。检测到豚鼠的 PAP 受体特异性 PCR 片段的特异性扩增，但未检测到狗唾液腺的特异性扩增。 向 3 X … 更多 豚鼠和狗下颌下腺注射 mRNA 的金爪鱼卵母细胞进行电生理学分析。应用 1 muM PAP 在注射了豚鼠而非狗颌下腺 mRNA 的卵母细胞中引发了小电流。4 PAP 刺激了豚鼠颌下腺切片中的粘蛋白释放。5 PAP 不能释放到细胞外，而是保留在细胞内。为了评估其细胞内活性，检查了PAP对膜部分中Na + 、K + -ATP酶活性的影响。 PAF 抑制狗颌下腺膜制剂中的 Na+, K+-ATP 酶。 PAP 受体拮抗剂 BN 50739 可以拮抗低浓度而非高浓度 PAP 的抑制作用。PAP 诱导的 Na^ , K^ -ATP 酶抑制的动力学分析表明，PAP 对 Na^ , K^ -ATP 酶的抑制不是由于 PAP 在酶上 K^ - 或 Na^ - 结合位点的竞争，而是由于复杂的抑制机制。这些结果表明 l : PAP生物合成通过重塑途径调节自主神经，2：PAP 受体在豚鼠唾液腺中表达并起到刺激分泌反应的作用，3：PAP 可能作为细胞内信号信使调节唾液腺的分泌反应。较少的

Platelet-Activating Factor (PAP) was released from a variety of inflammatory and immune-related cells. Moreover, PAF production has been demonstrated in a wider variety of cells and tissues, and suggested that PAF plays various physiological and pathological roles. We have previously shown that PAF is generated upon physiological stimulations in dog salivary gland cells. The present study examined the regulation of PAP biosynthesis and its role in secretory response in salivary glands.1 Acetylcholine (ACh), phenyleprine, isoproterenol and 8Br-cyclic AMP increased lyso-PAP : acetylCoA acetyltransferase (ACT) and DDT-insensiteve cholinephosphotransferase. ACh and phenylephrine increased ACT, and PAP generation in a Ca^2^+-dependent manner.2 PAP receptor expression in salivary glands was studied by examining PAF receptor gene expression using the RT-PCR technique. The specific amplification of PAP receptor-specific PCR fragment from guinea pig, but not dog salivary glands was detected.3 X … More enopus laevis oocytes injected with mRNA from submandibular glands of guinea pig and dogs were electrohysiologically analysed. Application of 1 muM PAP elicited a small current in the oocytes injected with mRNA from guinea pig but not dog submandibular glands.4 PAP stimulated mucin release in the slice of gunea pig submandibular glands.5 PAP is not releasable out of the cells but retained intracellulary in the cells. To assess its intracellular activity, the effect of PAP on Na^+, K^+-ATPase activity in the membrane fraction was examined. PAF inhibited Na^+, K^+-ATPase in the membrane preparations of dog submandibular glands. The inhibitory effect of a low concentration but not of high concentrations of PAP was antagonized by a PAP-receptor antagonists, BN 50739. Kinetic analysis of PAP-induced inhibition of Na^+, K^+-ATPase suggests that the inhibition of Na^+, K^+-ATPase by PAP is not due to competition by PAP at K^+-or Na^+-binding sites on the enzyme, but by complex inhibitory mechanisms.These results suggested that l : PAP biosynthesis is regulated autonomic nerve via remodelling pathway, 2 : PAP receptor is expressed guinea pig salivary gland and functions to stimulate secretory response, 3 : PAP may act as intracellular signal messenger to modulate secretory response in salivary glands. Less