Inhibitory effect of GABA on sympathetic neurotransmission in rabbit ear artery.
Inhibitory effect of GABA on sympathetic neurotransmission in rabbit ear artery.
复制标题
GABA 对兔耳动脉交感神经传递的抑制作用。
DOI：
--
复制
发表时间：
1985
影响因子：
--
通讯作者：
A. Meli
中科院分区：
文献类型：
--
作者：
S. Manzini;C. Maggi;A. Meli
GABA 100 μ M抑制兔耳动脉由各种频率的场刺激引起的神经源性血管收缩反应。GABA对静息张力和去甲肾上腺素（0.05-5 μ M）和高K+（24-54 mM）诱导的紧张性收缩均无效。GABA对场刺激诱导的血管收缩的有效性与刺激频率呈负相关。GABA的这种作用被选择性GABAB激动剂如巴氯芬（100 μ M）模拟，但不被选择性GABAA激动剂如蝇蕈醇（100 μ M）和高牛磺酸（100 μ M）模拟。选择性GABAB拮抗剂5-氨基戊酸（1 mM）和高牛磺酸（100 μ M）完全抑制GABA对场刺激诱导的血管收缩的抑制作用。GABA的作用也被选择性GABAA拮抗剂印防己毒素（100 μ M）部分逆转;然而，这种药物“本身”决定了场刺激诱导的收缩幅度的增加，这反过来又可能决定了GABA的次要作用。总之，这些数据表明，GABA可以通过刺激GABAB亚型的连接前受体来抑制兔耳动脉交感神经传递。
GABA 100 microM inhibited neurogenic vasoconstrictor responses elicited in rabbit ear artery by field stimulation at various frequencies. GABA was ineffective both on resting tone and on noradrenaline (0.05-5 microM)- and high-K+ (24-54 mM)-induced tonic contraction. GABA effectiveness against field stimulation-induced vasoconstriction was inversely related to the frequency of stimulation. This action of GABA was mimicked by a selective GABAB agonist, such as baclofen (100 microM), but not by selective GABAA agonists as muscimol (100 microM) and homotaurine (100 microM). The selective GABAB antagonists 5-aminovaleric acid (1 mM) and homotaurine (100 microM) completely suppressed the inhibitory effect of GABA on field stimulation-induced vasoconstrictions. GABA action was partially reversed also by the selective GABAA antagonist picrotoxin (100 microM); however, this drug "per se" determined an increase in amplitude of field stimulation-induced contractions which in turn could have determined the minor effect of GABA. As a whole these data suggest that GABA can inhibit sympathetic neurotransmission in rabbit ear artery through the stimulation of a prejunctional receptor of the GABAB subtype.