Alshuaib W B, Mathew M V
Physiology Department, Faculty of Medicine, Kuwait University, Safat, Kuwait.
J Neurosci Res. 1998 Jun 1;52(5):521-9. doi: 10.1002/(SICI)1097-4547(19980601)52:5<521::AID-JNR4>3.0.CO;2-E.
In the Drosophila mutant dunce, short-term memory is deficient and intracellular cyclic adenosine monophosphate (cAMP) concentration is elevated. We examined the effect of increased cAMP concentration on the potassium current. The conventional whole-cell technique was applied to cultured "giant" Drosophila neurons derived from cell-division arrested embryonic neuroblasts. Potassium membrane currents were measured from: 1) control wild-type neurons, 2) wild-type neurons with dibutyryl cAMP and theophylline in the culture media for 2 days (db-cAMP-treated), and 3) dunce neurons. Delayed-rectifier potassium current was greater in both dunce neurons and db-cAMP-treated wild-type neurons than in control wild-type neurons. This result indicates that the neuronal potassium current is increased by the long-term increase of cAMP. Conceivably, altered neuronal excitability in the dunce mutant could disrupt the processing of neural signals necessary for learning and memory.
在果蝇突变体“笨蛋”中，短期记忆存在缺陷，细胞内环状腺苷单磷酸（cAMP）浓度升高。我们研究了cAMP浓度升高对钾电流的影响。采用传统的全细胞技术，对源自细胞分裂停滞的胚胎神经母细胞培养的“巨型”果蝇神经元进行研究。从以下几类神经元测量钾膜电流：1）对照野生型神经元；2）在培养基中添加二丁酰cAMP和茶碱培养2天的野生型神经元（经二丁酰cAMP处理）；3）“笨蛋”神经元。“笨蛋”神经元和经二丁酰cAMP处理的野生型神经元中的延迟整流钾电流均大于对照野生型神经元。这一结果表明，cAMP的长期增加会使神经元钾电流增大。可以想象，“笨蛋”突变体中神经元兴奋性的改变可能会扰乱学习和记忆所需的神经信号处理过程。
