大白鼠上丘脑片深层部突触传递和LTP的研究

在大白鼠上丘脑片深层部的中层或深层给电刺激、分别在径向对应的深层或中层,记录到诱发的突触后场电位.以100Hz、1秒的强直刺激首次在上丘的深层部引出了长时程突触增强(LTP).N-甲基-D-天冬氨酸(NMDA)受体的选择性拮抗剂2-氨基-5-磷酸戊酸盐(APV)对LTP的阻断效应表明,NMDA受体不仅对上丘深层部LTP的产生有作用.而且也与LTP的维持有关.突触后场电位的幅度受APV或兴奋性氨基酸受体的非选择性拮抗剂犬尿喹啉酸(KYNA)的作用而减小,受γ-氨基丁酸(GABA)A型受体的选择性拮抗剂荷包牡丹碱(Bicu)的作用而增加,表明谷氨酸能神经递质在上丘深层部的兴奋性突触传递中起着重要作用,并且这些突触传递也受到GABA能抑制性突触的调节.

THE SYNAPTIC TRANSMISSION AND LTP WITHIN THE DEEP DIVISION OF THE SUPERIOR COLLICULUS IN THE BRAIN SLICES OF THE RAT

The postsynaptic field potentials (PSPs) were recorded radially in the intermediate layers or deep layers respectively after stimulating the deep layers or intermediate layers of the Superior Colliculus in the brain slices of the rat. Long-term potentiation (LTP) was. for the first time, elicited in the deep division of the Superior Colliculus by the tetanic stimulation of 100Hz for 1s . The blocking effect of D, L-amino-5-phosphonovalerate (APV) . a selective antagonist for N-methyl-D-aspartate (NMDA) receptor, on LTP indicated that the NMDA receptors were not only involved in initiation but also in maintenance of LTP in the deep collicular division of the rat. The amplitudes of PSPs were declined by APV or kynurenic acid (KYNA) . a relatively non - selective antagonist for three types of the excitatory amino acid (EAA) receptors; and facilitated to enhance by bicuculline (Bicu) . an antagonist for A type of r-amino butyric (GABA) receptors, suggesting glutamatergic neurotransmitters play an important role in the excitatory synaptic transmission within the deep collicular division, which is modulated by the inhibitory GABAergic synapses.