Sato E, Nakamura O, Ito S
Dev Biol. 1983 Jun;97(2):460-7. doi: 10.1016/0012-1606(83)90103-3.
The ionic dependency and transmission of epidermal action potentials have been examined from tailbud to hatching stages of newt embryos. Previously we have reported that the epidermal action potential is composed of a fast- and slow-action component; only the slow-action component, however, is transmitted to other cells. We address in this report the mechanism by which these responses are mediated. The slow-action potential is not produced in Na+-free saline, tricaine saline, or following the application of TTX, and thus appears to be Na+ dependent. The fast-action potential on the other hand is blocked by application of Co2+ and verapamil saline and thus appears to be Ca2+ dependent. The slow-action potentials appear to be chemically transmitted since they are transmitted even to those cells which are electrically uncoupled at low intracellular pH (NaHCO3 + HCl, pH 6.2). Furthermore 1 microM curare and atropine are inhibitory to transmission of the slow potential. Epidermal cells of the newt embryo are sensitive to acetylcholine (ACh) applied by hydrostatic ejection through a micropipet. The latter observation further suggests that propagation of the slow-action potential is, in part, a chemical event.
从蝾螈胚胎的尾芽期到孵化期，对表皮动作电位的离子依赖性和传导进行了研究。此前我们曾报道，表皮动作电位由快速和慢速动作成分组成；然而，只有慢速动作成分会传导至其他细胞。在本报告中，我们探讨了这些反应的介导机制。在无钠溶液、三卡因溶液或应用TTX后，不会产生慢速动作电位，因此似乎依赖于钠离子。另一方面，快速动作电位会被应用钴离子和维拉帕米溶液所阻断，因此似乎依赖于钙离子。慢速动作电位似乎是通过化学方式传导的，因为即使在细胞内低pH值（NaHCO3 + HCl，pH 6.2）时与那些电不耦合的细胞之间，它们也能传导。此外，1微摩尔的箭毒和阿托品对慢速电位的传导有抑制作用。蝾螈胚胎的表皮细胞对通过微量移液器进行液压喷射施加的乙酰胆碱（ACh）敏感。后一观察结果进一步表明，慢速动作电位的传播部分是一个化学过程。
