Nishiyama A, Katoh K, Saitoh S, Wakui M
Membr Biochem. 1980;3(4):317-28. doi: 10.3109/09687688009063891.
The effect of cholinergic neural excitation by field stimulation on the tension of the contractile system (myoepithelial cells) was investigated in superfused segments of rat salivary glands (sublingual, submaxillary, and parotid). Electric field stimulation evoked gland tissue contraction of a few mg, which was blocked by addition of TTX or atropine. The order of the magnitude of the contraction per wet tissue weight was sublingual greater than submaxillary greater than parotid. This correlates with the order of the distribution of myoepithelial cells described in morphological investigations. Cholinergic stimulants induced contraction in all salivary glands, but adrenergic stimulants hardly evoked contraction in the sublingual gland, whereas those drugs evoked a considerable amount of contraction in the submaxillary gland. These findings seem to suggest that the contraction may originate in the myoepithelial cells. The omission of Na from the superfusing solution quickly abolished the contraction evoked by field stimulation but not the contraction induced by ACh. The omission of Ca from the solution reduced the contraction evoked not only by field stimulation but also by ACh and by high K. The results suggest that extracellular Ca is important for the initiation of myoepithelial contraction.
通过场刺激对胆碱能神经兴奋对大鼠唾液腺（舌下腺、下颌下腺和腮腺）灌流节段收缩系统（肌上皮细胞）张力的影响进行了研究。电场刺激引起腺体组织收缩数毫克，添加TTX或阿托品可阻断这种收缩。每湿组织重量收缩幅度的顺序为舌下腺大于下颌下腺大于腮腺。这与形态学研究中描述的肌上皮细胞分布顺序相关。胆碱能兴奋剂在所有唾液腺中均诱导收缩，但肾上腺素能兴奋剂在下颌下腺几乎不引起收缩，而这些药物在舌下腺引起相当程度的收缩。这些发现似乎表明收缩可能起源于肌上皮细胞。灌流液中去除Na可迅速消除场刺激引起的收缩，但不能消除ACh诱导的收缩。溶液中去除Ca不仅降低了场刺激引起的收缩，也降低了ACh和高K引起的收缩。结果表明细胞外Ca对肌上皮收缩的起始很重要。
