GABA in the paraventricular nucleus tonically suppresses baroreflex function: alterations during pregnancy.
GABA in the paraventricular nucleus tonically suppresses baroreflex function: alterations during pregnancy.
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室旁核中的 GABA 强直性抑制压力感受反射功能：妊娠期间的变化。
DOI：
10.1152/ajpregu.00736.2010
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
Brooks,VirginiaL
中科院分区：
文献类型：
--
作者：
Page,MollieC;Cassaglia,PriscilaA;Brooks,VirginiaL
已经确定，GABA能输入下丘脑室旁核（PVN）紧张性抑制心率和几种交感神经的活动。然而，GABA是否同样抑制PVN控制的压力感受器反射功能，以前没有调查。为了检验这一假设，确定是否微量注射GABA A拮抗剂荷包牡丹碱到PVN增强麻醉雌性处女大鼠的压力感受性反射。此外，由于妊娠期间PVN前自主神经元的GABA能抑制降低，因此还确定了PVN荷包牡丹碱给药对妊娠动物压力感受器反射功能的影响是否较小。在未孕大鼠，PVN微量注射荷包牡丹碱，压力反射增益和最大心率水平（P< 0.05）（增益，从1.6 ± 0.6到3.8 ± 1.3 bpm/mmHg;最大值，从406 ± 18到475 ± 14 bpm）和腰交感神经活动（增益从2.6 ± 0.7至4.8 ± 1.6%/mmHg;最大值，149 ± 32至273 ± 48%），表明PVN GABA通常抑制压力反射功能。妊娠降低心率压力反射增益（妊娠，0.9 ± 0.3bpm/mmHg;处女，1.9 ± 0.2bpm/mmHg;P< 0.05）。妊娠大鼠给予PVN荷包牡丹碱后，压力反射增益增加较小（P< 0.01）（妊娠，0.6 ± 0.1 bpm/mmHg;处女，2.4 ± 0.9 bpm/mmHg）和最大（妊娠，33 ± 7 bpm;处女，75 ± 12 bpm;P< 0.05）。总的来说，这些数据表明，PVN通常通过紧张性GABA能输入抑制压力感受器反射，这种抑制在怀孕期间较少。
It is well established that GABAergic inputs to the paraventricular nucleus of the hypothalamus (PVN) tonically suppress heart rate and the activity of several sympathetic nerves. However, whether GABA similarly inhibits PVN control of baroreflex function has not been previously investigated. To test this hypothesis, it was determined whether microinjection of the GABAAantagonist, bicuculline, into the PVN enhances the baroreflex in anesthetized female virgin rats. In addition, because GABAergic inhibition of PVN preautonomic neurons is decreased during pregnancy, it was also determined whether the effects of PVN bicuculline administration on baroreflex function were less in pregnant animals. In virgin rats, PVN microinjection of bicuculline increased (P< 0.05) baroreflex gain and maximum levels of heart rate (gain, from 1.6 ± 0.6 to 3.8 ± 1.3 bpm/mmHg; maximum, from 406 ± 18 to 475 ± 14 bpm) and of lumbar sympathetic nerve activity (gain from 2.6 ± 0.7 to 4.8 ± 1.6%/mmHg; maximum, 149 ± 32 to 273 ± 48%), indicating that PVN GABA normally suppresses baroreflex function. Pregnancy decreased heart rate baroreflex gain (pregnant, 0.9 ± 0.3 bpm/mmHg; virgin, 1.9 ± 0.2 bpm/mmHg;P< 0.05). Following PVN bicuculline administration in pregnant rats, smaller (P< 0.01) increments in baroreflex gain (pregnant, 0.6 ± 0.1 bpm/mmHg; virgin, 2.4 ± 0.9 bpm/mmHg) and maximum (pregnant, 33 ± 7 bpm; virgin, 75 ± 12 bpm;P< 0.05) were produced. Collectively, these data suggest that the PVN normally inhibits the baroreflex via tonic GABAergic inputs and that this inhibition is less during pregnancy.