Meredith Rhiannon M, Floyer-Lea Anna M, Paulsen Ole
University Laboratory of Physiology, Oxford University, Oxford, OX1 3PT, United Kingdom.
J Neurosci. 2003 Dec 3;23(35):11142-6. doi: 10.1523/JNEUROSCI.23-35-11142.2003.
The induction rules of synaptic plasticity are important for the functional operation of a neural network. We asked whether such synaptic plasticity rules change during development from juvenile to adult animals. Using perforated patch and whole-cell recordings from CA1 pyramidal cells in hippocampal slices, we demonstrate here that the postsynaptic requirements for induction of associative long-term potentiation (LTP) shift gradually. Presynaptic stimulation paired with single postsynaptic action potentials became progressively less effective at inducing LTP with advancing developmental age until, in adult hippocampus, postsynaptic bursts of action potentials were necessary to induce synaptic potentiation. This developmental change might be accounted for by changes in GABA(A) receptor-mediated inhibition known to occur in the hippocampus during this postnatal period, because blocking GABA(A) receptor-mediated inhibition re-established the effectiveness of single postsynaptic action potentials at inducing LTP in adult hippocampus. These data reveal a gradual shift in the induction rules for LTP, explained by a maturational change in GABAergic inhibition, and could have implications for our understanding of the role of inhibition in information processing in the brain.
突触可塑性的诱导规则对于神经网络的功能运作至关重要。我们探究了在从幼年动物到成年动物的发育过程中，此类突触可塑性规则是否会发生变化。利用海马切片中CA1锥体神经元的穿孔膜片钳和全细胞记录技术，我们在此证明，诱导联合性长时程增强（LTP）的突触后条件逐渐发生改变。随着发育年龄的增长，与单个突触后动作电位配对的突触前刺激诱导LTP的效果逐渐降低，直至在成年海马体中，需要突触后动作电位爆发才能诱导突触增强。这种发育变化可能是由于在此出生后时期海马体中已知发生的GABA(A)受体介导的抑制作用的变化所致，因为阻断GABA(A)受体介导的抑制作用可重新建立单个突触后动作电位在成年海马体中诱导LTP的有效性。这些数据揭示了LTP诱导规则的逐渐转变，这是由GABA能抑制作用的成熟变化所解释的，并且可能对我们理解抑制作用在大脑信息处理中的作用具有启示意义。
