A physiological role for protoporphyrin IX photodynamic action in the rat Harderian gland?
A physiological role for protoporphyrin IX photodynamic action in the rat Harderian gland?
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DOI：
10.1046/j.1365-201x.2003.01177.x
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发表时间：
2003-10
期刊：
影响因子：
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通讯作者：
Z. Cui;Y. D. Zhou;Y. Satoh;Y. Habara
中科院分区：
文献类型：
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作者：
Z. Cui;Y. D. Zhou;Y. Satoh;Y. Habara
目的哈氏腺是一种分泌脂质的外分泌腺，腺细胞中含有大量的卟啉（主要是原卟啉IX，PPIX），其生理意义尚不清楚。方法本研究应用Fura-2检测细胞内钙离子浓度（[Ca 2 +]c）变化的可行性。结果Fura-2负载的细胞在340/380 nm光激发下，[Ca 2 +]c自发增加，表明Fura-2负载的细胞在340/380 nm光激发下具有光动力学作用。与此相反，与可见光谱钙探针Fluo-3（λ（ex）= 475 nm），卡巴胆碱在10微米诱导[Ca 2 +]c增加; [Ca 2 +]c没有改变卡巴胆碱刺激。340/380 nm光的短暂照射诱导Fluo-3负载细胞的[Ca 2 +]c大幅增加。用外源光敏剂磺化铝酞菁（SALPC）和可见光（>580 nm）证实了[Ca 2 +]c增加的光动力学刺激。的[Ca 2 +]c增加的波长依赖性与激发光谱的孤立的哈氏腺细胞。结论PPIX在大鼠哈氏腺细胞中起光敏剂的作用，当被UVA和日光的蓝色成分激活后，产生单线态氧，引起[Ca 2 +]c升高和分泌反应。PPIX的光动力作用也可能在光夹带的中央昼夜节律钟中发挥潜在的作用。
AIMS The lipid-secreting exocrine Harderian gland contains a large amount of porphyrins (mainly protoporphyrin IX, PPIX) in the glandular cells, the physiological significance of which is rather poorly understood. METHODS In the present study, the possibility of using Fura-2 to measure intracellular calcium ([Ca2+]c) changes in these cells was assessed. RESULTS It was found that when Fura-2-loaded cells were excited by light at 340/380 nm, [Ca2+]c increased spontaneously, indicating a photodynamic action powered by light at 340/380 nm. In contrast, with the visible spectrum calcium probe Fluo-3 (lambda(ex) = 475 nm), carbachol at 10 microm induced [Ca2+]c increase; [Ca2+]c did not change without carbachol stimulation. Brief illumination with light at 340/380 nm induced a large [Ca2+]c increase in Fluo-3-loaded cells. Photodynamic stimulation of [Ca2+]c increase was confirmed with an exogenous photosensitizer sulphonated aluminium phthalocyanine (SALPC) and visible light (>580 nm). The wavelength-dependence of the [Ca2+]c increase correlates well with the excitation spectrum of the isolated Harderian glandular cells. CONCLUSION These data suggest that PPIX present in rat Harderian glandular cells plays the role of a photosensitizer which upon activation by UVA and blue components of daylight and subsequent singlet oxygen generation, triggers [Ca2+]c increase and secretory response. The PPIX photodynamic action may also play a potential role in photic entrainment of the central circadian clock.