Wee E L, Phillips N J, Babiarz B S, Zimmerman E F
J Embryol Exp Morphol. 1980 Aug;58:177-93.
Morphological studies have shown that the pterygopalatine ganglion in the day-14.5 mouse palatal shelf lies adjacent to the putative contractile system of region-2 cells in the posterior palate. It is of interest to learn whether the ganglion could influence rotation of the palate. Results of embryo culture experiments showed that acetylcholine appeared to play a role in posterior shelf rotation since cholinergic agents (pyridostigmine, bethanechol and carbachol) stimulated elevation of that end of the palate. To characterize the putative receptors mediating the effects of the cholinergic agonists on palate shelf elevation, muscarinic or nicotinic antagonists were introduced into the emrbyo culture system. Atropine, a muscarinic blocking agent, did not produce any significant effect on palate shelf rotation when tested in overnight and 2 h embryo cultures at 3 X 10(-5) M and 10(-4) M, respectively. Neither did atropine inhibit significantly the stimulation produced by 10(-8) M bethanechol, Thus, the cholinergic effect was probably not on muscarinic receptors of the contractile system. However, hexamethonium, a nicotinic antagonist, at 10(-6) M and 10(-4) M profoundly inhibited posterior shelf rotation to about 35% of the control value in a 2 h incubation. In addition, 10(-4) M hexamethonium inhibited posterior palate rotation to 11% of the control value after overnight culture. Furthermore, hexamethonium was able to reverse the stimulation of posterior rotation produced by carbachol. Partial inhibition of palate rotation by hexamethonium was also demonstrated when pregnant dams were injected with drug at doses approximately corresponding to 10(-6) and 10(-4) M. Hexamethonium treatment resulted in approximately 30% of the palates not completely rotated at day 15.5 compared to only 9.3% in the control. Hexamethoniuim also produced a significant increase in the palate gap and a comparable decrease in palate fusion. These effects were slightly greater at the posterior end of the palate. Thus, the cholinergic ganglion in the posterior palate may play a role in regulating shelf rotation at that end through a nicotinic pathway.
形态学研究表明，在胚胎发育第14.5天的小鼠腭板中，翼腭神经节位于腭后部区域2细胞的假定收缩系统附近。了解该神经节是否会影响腭的旋转很有意义。胚胎培养实验结果显示，乙酰胆碱似乎在腭后段旋转中起作用，因为胆碱能药物（吡啶斯的明、氨甲酰甲胆碱和卡巴胆碱）能刺激腭该端的抬高。为了确定介导胆碱能激动剂对腭板抬高作用的假定受体，将毒蕈碱或烟碱拮抗剂引入胚胎培养系统。毒蕈碱阻断剂阿托品在分别以3×10⁻⁵ M和10⁻⁴ M浓度进行过夜和2小时胚胎培养测试时，对腭板旋转未产生任何显著影响。阿托品也未显著抑制10⁻⁸ M氨甲酰甲胆碱产生的刺激作用，因此，胆碱能效应可能不是作用于收缩系统的毒蕈碱受体。然而，烟碱拮抗剂六甲铵在10⁻⁶ M和10⁻⁴ M浓度下，在2小时孵育中能将腭后段旋转显著抑制至对照值的约35%。此外，10⁻⁴ M六甲铵在过夜培养后能将腭后段旋转抑制至对照值的11%。此外，六甲铵能够逆转卡巴胆碱对后段旋转的刺激作用。当给怀孕母鼠注射大致相当于10⁻⁶ M和10⁻⁴ M剂量的药物时，也证明了六甲铵对腭旋转有部分抑制作用。与对照组仅9.3%相比，六甲铵处理导致在第15.5天时约30%的腭未完全旋转。六甲铵还使腭间隙显著增加，腭融合程度相应降低。这些效应在腭的后端稍大。因此，腭后部的胆碱能神经节可能通过烟碱途径在调节该端的腭板旋转中发挥作用。
