[Effects of chronic exposure to beta-amyloid-peptide25-35 on the mRNA expressions of voltage-gated outward potassium channel subunits in cultured rat hippocampal neurons].
OBJECTIVE
To investigate mRNA expression changes of voltage-gated outward potassium channel subtypes in cultured rat hippocampal neurons after chronic exposure to beta-amyloid-petitde25-35 (beta-AP25-35).


METHODS
mRNA expression was detected by RT-PCR, comparative expression levels were determined by imaging densitometer.


RESULTS
Delayed rectifying (Kv2.1, Kv1.5), transient outward (Kv1.4, Kv4.2) and large conductance calcium-activated (rSlo) potassium channel mRNA were expressed in cultured rat hippocampal. In the presence of beta-AP25-35 3 mumol.L-1 for 24 h, the relative expression level of Kv2.1 was significantly increased (n = 3, P < 0.05); the other subtypes were not changed obviously (n = 3, P > 0.05). The increase of Kv2.1 mRNA mainly happened between 24 and 36 h after exposure to beta-AP25-35. After exposure to beta-AP25-35 for 60 h, Kv2.1 mRNA decreased significantly (n = 3, P < 0.01).


CONCLUSIONS
The upregulation of Kv2.1 on transcription levels may be involved in the enhancement of delayed rectifying outward potassium (Ik) current induced by beta-AP25-35.
Jin
Hong-wei
HW
Institute of Materia Medica, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100050, China.
Zhang
Wei
W
Wang
Xiao-liang
XL
D016229:Amyloid beta-Peptides / Q000633:toxicity*; D000818:Animals; D000831:Animals, Newborn; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D051668:Delayed Rectifier Potassium Channels; D005260:Female; D015870:Gene Expression / Q000187:drug effects*; D006624:Hippocampus / Q000166:cytology*; D008297:Male; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010446:Peptide Fragments / Q000633:toxicity*; D015221:Potassium Channels / Q000096:biosynthesis* / Q000235:genetics; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D051669:Shab Potassium Channels
D016229:Amyloid beta-Peptides; D051668:Delayed Rectifier Potassium Channels; C496991:Kcnb1 protein, rat; D010446:Peptide Fragments; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D012333:RNA, Messenger; D051669:Shab Potassium Channels; C074636:amyloid beta-protein (25-35)