Abdollahi M, Dehpour A, Kazemian P
Faculty of Pharmacy, Department of Toxicology and Pharmacology, Tehran University of Medical Sciences, 14155-6451, Tehran, Iran.
Pharmacol Res. 2000 Dec;42(6):591-7. doi: 10.1006/phrs.2000.0731.
The effects of cadmium, l-arginine (nitric oxide precursor) and N(omega)-nitro-l-arginine methyl ester (l -NAME) as a nitric oxide synthesis inhibitor and cotreatment of them on rat submandibular secretory function were studied. Pure submandibular saliva was collected intraorally by micro polyethylene cannula from anaesthetized rats using pilocarpine as secretagogue. Fourteen days treatment with 10 mg l(-1)cadmium as cadmium chloride in drinking water caused significant alterations on salivary function. Salivary flow rate, total protein concentration and amylase activity of saliva were decreased while secretion of calcium was increased by cadmium. Two weeks treatment of rats with l -arginine (2.25%) in drinking water caused an increase in submandibular gland weight. Flow rate was reduced by l-NAME. The total protein concentration of saliva was increased by l-arginine while decreased by l-NAME. Calcium concentration of saliva was reduced by l-arginine and increased by l-NAME. Cotreatment of cadmium with l-arginine prevented cadmium-induced reduction of flow rate while l-NAME cotreatment potentiated cadmium-induced reduction of flow rate. l-arginine showed a preventive effect on cadmium-induced decrease of protein concentration and reached control levels. l-arginine potentiated cadmium-induced increase of saliva calcium concentration. It is confirmed that nitric oxide (NO) has a role in salivary gland function. It is also concluded that cadmium inhibitory effects on salivary gland function are modulated by the NO system as it is observed that the cadmium inhibitory effect on submandibular gland function is diminished by l-arginine and extended by l-NAME. Considering the properties of cadmium substitution for calcium in many intracellular events, different types of alterations can be discussed.
研究了镉、L-精氨酸（一氧化氮前体）和作为一氧化氮合成抑制剂的N（ω）-硝基-L-精氨酸甲酯（L-NAME）及其联合处理对大鼠下颌下腺分泌功能的影响。使用毛果芸香碱作为促分泌剂，通过微型聚乙烯插管从麻醉大鼠口腔内收集纯下颌下腺唾液。以10mg/L氯化镉形式的镉在饮用水中处理14天会导致唾液功能发生显著改变。镉会降低唾液流速、唾液总蛋白浓度和淀粉酶活性，同时增加钙的分泌。在饮用水中用L-精氨酸（2.25%）处理大鼠两周会导致下颌下腺重量增加。L-NAME会降低流速。L-精氨酸会增加唾液总蛋白浓度，而L-NAME会降低该浓度。L-精氨酸会降低唾液钙浓度，而L-NAME会增加该浓度。镉与L-精氨酸联合处理可防止镉诱导的流速降低，而L-NAME联合处理会增强镉诱导的流速降低。L-精氨酸对镉诱导的蛋白浓度降低具有预防作用，并达到对照水平。L-精氨酸会增强镉诱导的唾液钙浓度增加。证实一氧化氮（NO）在唾液腺功能中起作用。还得出结论，镉对唾液腺功能的抑制作用受NO系统调节，因为观察到L-精氨酸可减轻镉对下颌下腺功能的抑制作用，而L-NAME会增强该抑制作用。考虑到镉在许多细胞内事件中替代钙的特性，可以讨论不同类型的改变。
