Emmerling M R, Sobkowicz H M
Department of Neurology, University of Wisconsin, Madison 53706.
Hear Res. 1988 Feb-Mar;32(2-3):137-45. doi: 10.1016/0378-5955(88)90086-x.
The activities of the globular and asymmetric forms of acetylcholinesterase (AChE) were measured in the whole cochlea and cochlear turns of the developing postnatal mouse. The globular AChE forms (G4, G2 and G1) were present in each cochlear turn at birth. An asymmetric AChE form (A12) was detected in the midturn on the 4th postnatal day, and in the base and apex on the 7th postnatal day. The activities of all AChE molecular forms increased rapidly during the second postnatal week and reached a plateau by the 19th postnatal day. In the 26-day old mouse, G4 constitutes the largest proportion of total cochlear AChE (57%), G2/G1 being 37% and A12 being 6%. The distribution of the AChE forms among the different turns is as follows: the combined value of the activities of G2 and G1 AChE was the same in each turn; G4 was the major form in the base and midturn; and A12, the least abundant AChE form of all, was localized mainly in the base. Our results indicate that in the cochlea (1) the content of molecular forms is similar to that of other neuronal systems, (2) the expression of AChE molecular forms is developmentally regulated, and (3) the AChE isoenzymes develop and are distributed differentially along the cochlear length; resulting near maturity in the greater proportional expression of G4 and A12 in the base and midturn and G2/G1 in the apex.
在出生后发育阶段的小鼠全耳蜗及耳蜗各转中测量了乙酰胆碱酯酶（AChE）球状和不对称形式的活性。出生时，球状AChE形式（G4、G2和G1）存在于每个耳蜗转中。出生后第4天在耳蜗中部检测到一种不对称AChE形式（A12），出生后第7天在基部和顶部检测到。所有AChE分子形式的活性在出生后第二周迅速增加，并在出生后第19天达到平台期。在26日龄的小鼠中，G4占耳蜗总AChE的比例最大（57%），G2/G1为37%，A12为6%。AChE形式在不同耳蜗转中的分布如下：G2和G1 AChE活性的合并值在每个转中相同；G4是基部和中部的主要形式；而A12是所有形式中含量最少的，主要定位于基部。我们的结果表明，在耳蜗中：（1）分子形式的含量与其他神经元系统相似；（2）AChE分子形式的表达受发育调控；（3）AChE同工酶沿耳蜗长度发育并差异分布；在接近成熟时，基部和中部G4和A12的比例表达较高，顶部G2/G1的比例表达较高。
