Effects of systemic administration of iptakalim on extracellular neurotransmitter levels in the striatum of unilateral 6-hydroxydopamine-lesioned rats.
The function of ATP-sensitive potassium (KATP) channels in nigrostriatal pathway in Parkinson's disease (PD) was studied by employing a novel KATP channel opener iptakalim (Ipt). Apomorphine-induced rotation behavior test and microdialysis experiment were carried out in unilateral 6-hydroxydopamine (6-OHDA) lesioned rats. Behavior test showed that systemic administration of Ipt failed to significantly alleviate apomorphine-induced rotation in unilateral 6-OHDA-lesioned PD model rats. However, using in vivo microdialysis in this PD model rats, it was found that Ipt could increase extracellular dopamine levels in the lesioned side of the striatum and decrease dopamine levels in the intact side of the striatum. Meanwhile, Ipt had no influence on glutamate levels in the intact side, but it did decrease glutamate levels in the lesioned side of the striatum of PD rats. Additionally, in primary cultured rat astrocytes, 6-OHDA decreased overall glutamate uptake activity, but this decrease was recovered and glutamate uptake activity was restored by the opening of KATP channels induced by Ipt and pinacidil. The classical KATP channel blocker glibenclamide completely abolished the effects of Ipt and pinacidil. The present study suggests that (i) the function of KATP channels in the lesioned and intact nigrostriatal pathway is different in unilateral 6-OHDA-lesioned PD model rats. (ii) KATP channels regulate extracellular neurotransmitter levels in the striatum of unilateral 6-OHDA-lesioned rats and may play neuroprotective roles due to their effects on glutamate transporters.
Wang
Sen
S
Department of Pharmacology and Neurobiology, Nanjing Medical University, Nanjing, Jiangsu Province, PR China.
Hu
Li-fang
LF
Zhang
Yun
Y
Sun
Tao
T
Sun
Ye-hong
YH
Liu
Su-yi
SY
Ding
Jian-hua
JH
Wu
Jie
J
Hu
Gang
G
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D000959:Antihypertensive Agents / Q000494:pharmacology; D001058:Apomorphine / Q000494:pharmacology; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism; D002478:Cells, Cultured; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism* / Q000503:physiopathology; D004195:Disease Models, Animal; D004298:Dopamine / Q000378:metabolism; D018491:Dopamine Agonists / Q000494:pharmacology; D045604:Extracellular Fluid / Q000187:drug effects / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis; D018377:Neurotransmitter Agents / Q000378:metabolism*; D020734:Parkinsonian Disorders / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D020110:Pinacidil / Q000494:pharmacology; D024661:Potassium Channels, Inwardly Rectifying / Q000819:agonists / Q000378:metabolism*; D017729:Presynaptic Terminals / Q000187:drug effects / Q000378:metabolism*; D011437:Propylamines / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology
D000959:Antihypertensive Agents; D018491:Dopamine Agonists; C502260:N-(1-methylethyl)-1,1,2-trimethylpropylamine; D018377:Neurotransmitter Agents; D024661:Potassium Channels, Inwardly Rectifying; D011437:Propylamines; D018698:Glutamic Acid; D020110:Pinacidil; D000255:Adenosine Triphosphate; D001058:Apomorphine; D004298:Dopamine