Wang Xu-wu, Kong Wei-jia
Department of Otorhinolaryngology, Union Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Zhonghua Er Bi Yan Hou Tou Jing Wai Ke Za Zhi. 2005 Nov;40(11):830-4.
To investigate modulation of gamma-aminobutyric acid (GABA) and its receptors on medial vestibular nucleus neurons in vivo.
Twenty-six male Wistar rats were used. gamma-aminobutyric acid, bicuculline (BIC, gamma-aminobutyric acid A receptor antagonist) and 2-hydroxysaclofen (SAC, gamma-aminobutyric acid B receptor antagonist) were microiontophoresed on medial vestibular nucleus (MVN) neurons to determine the effects of gamma-aminobutyric acid and its antagonists on the neuronal firing rates of medial vestibular nucleus in rats in vivo.
Microiontophoretic application of y-aminobutyric acid at 10, 30, 50 nA electric current produced inhibitory responses on 42 MVN neurons, these responses were dose-dependent decreases, firing rates (x +/- s) of MVN neurons decreased form (14.8 +/- 5.6) times/s to (8.7 +/- 3.4) times/s, (4.1 +/- 1.6) times/s and (2.2 +/- 1.1) times/s respectively; microiontophoretic application of bicuculline in 37 MVN neurons, 86.5% (32/37) neurons produced excitatory responses, 13.5% (5/37) neurons didn't response, firing rates of MVN neurons increased form (15.3 +/- 6.3) times/s to (16.8 +/- 7.1) times/s, (25.9 +/- 10.1) times/s and (32.7 +/- 11.3) times/s respectively at 10, 30, 50 nA electric current, which were dose-dependent increases, and the inhibitory responses of gamma-aminobutyric acid on MVN neurons were blocked by bicuculline completely; however, microiontophoretic application of 2-hydroxysaclofen didn't produced responses as bicuculline did.
Modulation of gamma-aminobutyric acid on medial vestibular nucleus neurons was mediated by y-aminobutyric acid A receptor in vivo.
研究体内γ-氨基丁酸（GABA）及其受体对内侧前庭核神经元的调节作用。
选用26只雄性Wistar大鼠。将γ-氨基丁酸、荷包牡丹碱（BIC，GABA A受体拮抗剂）和2-羟基-saclofen（SAC，GABA B受体拮抗剂）微离子导入内侧前庭核（MVN）神经元，以确定γ-氨基丁酸及其拮抗剂对体内大鼠内侧前庭核神经元放电频率的影响。
以10、30、50 nA电流微离子导入γ-氨基丁酸对42个MVN神经元产生抑制反应，这些反应呈剂量依赖性降低，MVN神经元的放电频率（x±s）分别从（14.8±5.6）次/秒降至（8.7±3.4）次/秒、（4.1±1.6）次/秒和（2.2±1.1）次/秒；对37个MVN神经元微离子导入荷包牡丹碱，86.5%（32/37）的神经元产生兴奋反应，13.5%（5/37）的神经元无反应，在10、30、50 nA电流下，MVN神经元的放电频率分别从（15.3±6.3）次/秒增加到（16.8±7.1）次/秒、（25.9±10.1）次/秒和（32.7±11.3）次/秒，呈剂量依赖性增加，且γ-氨基丁酸对MVN神经元的抑制反应被荷包牡丹碱完全阻断；然而，微离子导入2-羟基-saclofen未产生如荷包牡丹碱那样的反应。
体内γ-氨基丁酸对内侧前庭核神经元的调节作用由GABA A受体介导。
