Baclofen and adenosine inhibit synaptic potentials mediated by gamma-aminobutyric acid and glutamate release in rat nucleus accumbens.
Baclofen and adenosine inhibit synaptic potentials mediated by gamma-aminobutyric acid and glutamate release in rat nucleus accumbens.
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发表时间：
1991-08
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通讯作者：
N. Uchimura;R. North
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作者：
N. Uchimura;R. North
细胞内记录是由体外组织切片中的大鼠伏隔核神经元进行的；突触后电位（p.s.p.）是通过切片表面的局部电刺激引起的。 P.s.p.荷包牡丹碱 (30 µM) 部分阻断，6-氰基-2,3-二羟基-7-硝基喹喔啉 (CNQX，10 µM) 和 DL-2-氨基-5-磷酸戊酸 (APV，30 µM) 组合部分阻断，当所有三种拮抗剂同时使用时完全阻断。 γ-氨基丁酸 (GABA) 介导的 p.s.p. （在 CNQX 和 APV 中）和谷氨酸介导的 p.s.p. （荷包牡丹碱中）被巴氯芬 (10-300 µM)、腺苷 (10-300 µM) 和 N6-(2-苯基异丙基)腺苷 (0.1-3 µM) 抑制。茶碱竞争性拮抗腺苷的作用，表观解离平衡常数约为 15 microM。巴氯芬、腺苷和 N6-(2-苯基异丙基)腺苷引起小幅（小于 10 mV）超极化；电压钳实验表明这是由向外的钾电流引起的。结论是GABAB受体和腺苷A1受体的激活抑制伏隔核突触处谷氨酸和GABA的释放。
Intracellular recordings were made from rat nucleus accumbens neurons in a tissue slice in vitro; postsynaptic potentials (p.s.p.) were evoked by focal electrical stimulation of the slice surface. P.s.p. were partially blocked by bicuculline (30 microM), partially blocked by a combination of 6-cyano-2,3-dihydroxy-7-nitroquinoxaline (CNQX, 10 microM) and DL-2-amino-5-phosphonovaleric acid (APV, 30 microM) and completely blocked when all three antagonists were applied together. Both the gamma-aminobutyric acid (GABA)-mediated p.s.p. (in CNQX and APV) and the glutamate-mediated p.s.p. (in bicuculline) were inhibited by baclofen (10-300 microM), adenosine (10-300 microM) and N6-(2-phenylisopropyl)adenosine (0.1-3 microM). Theophylline competitively antagonized the action of adenosine with an apparent dissociation equilibrium constant of about 15 microM. Baclofen, adenosine and N6-(2-phenylisopropyl)adenosine caused small (less than 10 mV) hyperpolarizations; voltage clamp experiments indicated that this resulted from an outward potassium current. It is concluded that activation of GABAB receptors and adenosine A1 receptors inhibits the release of glutamate and GABA at synapses in the nucleus accumbens.