[Enhancement of NMDA receptor sensitivity by thrombin and its relationship with tissue transglutaminase].
OBJECTIVE
To explore the possible relationship between the thrombin induced potentiation of rat cerebellum granular cell N-methyl-D-aspartate (NMDA) receptor function and the change of intracellular tissue transglutaminase (tTG).


METHODS
Primary cultured rat cerebellum granular cells were pretreated by using thrombin (0.01 U/ml) with or without co-pretreatment of 0.5 x 10(-4) mol/L MDC (monodansylcadaverine, a tTG inhibitor) 30 minutes. Induce cells mentioned above to undergo apoptosis with different concentration of NMDA (0.1 x 10(-4) mol/L, 0.25 x 10(-4) mol/L and 0.5 x 10(-4) mol/L). Flowcytometer was applied 3 hours later to detect the changed function of NMDA receptor by counting percentage of apoptotic cells. RT-PCR was used to compare the tTG mRNA level in the cerebellum granular cells treated with NMDA of same dosage with/without thrombin pretreatment.


RESULTS
Thrombin pretreatment increased the percentage of apoptosis cells induced by NMDA [(8.3 +/- 0.5)% to (15.1 +/- 0.8)% at 0.1 x 10(-4) mol/L, (14.1 +/- 1.1)% to (23.8 +/- 0.7)% at 0.25 x 10(-4) mol/L, (26.8 +/- 1.9)% to (33.7 +/- 2.1)% at 0.5 x 10(-4) mol/L)]; and this effect was inhibited by co-pretreatment MDC with thrombin, cell apoptosis decreased to (5.8 +/- 1.2)%, (11.5 +/- 1.5)% and (19.0 +/- 1.7)%; Thrombin increased intracellular tTG mRNA levels comparing with those without thrombin pretreatment.


CONCLUSIONS
Thrombin potentiates rat cerebellum granular cell NMDA receptor function by increasing intracellular tissue transglutaminase.
Zeng
Fei
F
Department of Neurology, Renmin Hospital of Wuhan University, Wuhan 430060, China. frederic2000@etang.com
Yu
Shao-zu
SZ
Zeng
Qing-xing
QX
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016202:N-Methylaspartate / Q000494:pharmacology; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D013917:Thrombin / Q000494:pharmacology*; D011503:Transglutaminases / Q000235:genetics / Q000378:metabolism*
D012333:RNA, Messenger; D016194:Receptors, N-Methyl-D-Aspartate; D016202:N-Methylaspartate; D011503:Transglutaminases; D013917:Thrombin