Mitchell J B, Miller K, Dunwiddie T V
Department of Pharmacology, University of Colorado Health Sciences Center, Denver 80262.
Hippocampus. 1993 Jan;3(1):77-86. doi: 10.1002/hipo.450030108.
The results of several previous studies have suggested that pretreatment with adenosine can block the induction of long-term potentiation (LTP), although other studies have found no effect of adenosine on the induction of LTP. The interaction of adenosine with the induction of LTP in the rat hippocampal slice was investigated. Inhibition of synaptic responses by adenosine either prior to or immediately after high-frequency or theta-burst stimulation did not affect LTP measured after washout of the adenosine. The only conditions under which adenosine blocked the development of LTP was when it was given 3-5 minutes prior to the stimulation train. To understand how it was possible to induce LTP, during the period 1-3 minutes following adenosine when synaptic responses were virtually eliminated, evoked responses during the 100 Hz stimulation train were recorded. Although synaptic responses to low-frequency stimulation were virtually eliminated by adenosine, they reappeared during high-frequency stimulation. These results suggest that although adenosine can depress synaptic responses, an increase in neurotransmission during a high-frequency train can partially overcome this effect of adenosine, and the hypothesis that adenosine can selectively block LTP is not supported.
此前多项研究结果表明，腺苷预处理可阻断长时程增强（LTP）的诱导，不过其他研究发现腺苷对LTP的诱导并无影响。本研究对大鼠海马切片中腺苷与LTP诱导之间的相互作用进行了探究。在高频或θ波爆发刺激之前或之后立即给予腺苷对突触反应的抑制作用，在洗脱腺苷后对LTP的测量并无影响。腺苷阻断LTP发展的唯一情况是在刺激序列前3 - 5分钟给予。为了解如何诱导LTP，在给予腺苷后1 - 3分钟期间，当突触反应几乎消除时，记录了100Hz刺激序列期间的诱发反应。尽管腺苷几乎消除了对低频刺激的突触反应，但它们在高频刺激期间重新出现。这些结果表明，尽管腺苷可抑制突触反应，但高频刺激期间神经传递的增加可部分克服腺苷的这种作用，腺苷可选择性阻断LTP这一假设并不成立。
