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Adenosine inhibits spontaneous and glutamate-induced discharges of hippocampal CA1 neurons
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- Author:
- No author available
- Journal Title:
- ACTA PHYSIOLOGICA SINICA
- Issue:
- 4
- DOI:
- 10.3321/j.issn:0371-0874.2000.04.004
- Key Word:
- 腺苷;8-苯茶碱;8-环戊-1,3-二丙基黄嘌呤;格列苯脲;谷氨酸;海马脑片
Abstract： 应用细胞外记录单位放电技术, 在大鼠海马脑片上观察腺苷(adenosine, Ado)对CA1区神经元自发和谷氨酸所致癫痫样放电的影响.实验结果如下: (1) 20个海马CA1神经元在给予Ado (0.01～0.1 μmol/L)时自发放电频率降低, 且呈明显的剂量依赖性;(2) 在22个CA1单位, 应用腺苷受体非选择性拮抗剂8-苯茶碱(8-phenyltheophylline, 8-PT, 0.5 mmol/L)和腺苷A1受体选择性拮抗剂8-环戊-1,3-二丙基黄嘌呤(8-cyclopentyl-1,3-dipropylxanthine, DPCPX, 50 nmol/L)均可完全阻断腺苷的抑制效应; (3)在应用ATP敏感性钾通道抑制剂格列苯脲(glibenclamide, Gli, 15 mmol/L)的10个单位, 腺苷的上述抑制效应亦被阻断; (4)在15个单位, 预先用谷氨酸(glutamate, Glu, 0.2 mmol)灌流海马脑片2 min, CA1神经元放电频率明显增加, 表现为癫痫样放电, 灌流Ado (10 μmol/L)后则可抑制其癫痫样放电; (5) 10个CA1单位, 灌流8-PT (2 mmol/L)或DPCPX (200 nmol/L)均可阻断腺苷对谷氨酸效应的抑制作用; 对5个CA1单位应用Gli (7 mmol/L)亦可消除上述效应.结果提示: Ado与海马神经元上的A1受体结合后, 引起细胞膜上的ATP敏感性钾通道的开放, 从而对海马神经元自发放电及Glu所致的癫痫样放电呈现抑制作用.
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