| 摘要: |
| 目的： 一定程度上区分孤束核(NTS)内GABAA 和GABAB 受体对血压调节的作用。方法：NTS微注射、NTS损毁及电刺激下丘脑防御反应区，记录血压和心率。结果：GABAA受体拮抗剂荷包牡丹碱能逆转GABA摄取抑制剂3-哌啶甲酸引起的血压升高，GABAB受体拮抗剂CGP 35348则不能；谷氨酸使蝇蕈醇所致的血压升高小幅度下降，对GABAB受体激动剂引起的血压升高无明显影响；刺激下丘脑防御反应区引起的血压升高能被NTS部位注射荷包牡丹碱所阻断，GABAB受体拮抗剂CGP 35348不能。结论：NTS部位的GABAA和GABAB受体在对心血管功能的调控方面存在差异，这些差异可能是由于GABAA受体主要存在于突触后膜，GABAB受体主要存在于突触前膜所造成的。 |
| 关键词: 孤束核 受体，γ-氨基丁酸 下丘脑防御反应区 血压 |
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| Differences between GABAA and GABAB receptors of nucleus tractus solitarii in the regulation of cardiovascular activity in rats |
| 苏定冯,殷明,杨军,彭友清 |
| () |
| Abstract: |
| Objective: To determine whether there are some differences between GABAA and GABAB receptors in the regulation of cardiovascular activity in the nucleus tractus solitarii(NTS). Methods: Techniques of microinjection into NTS and lesion of NTS as well as electric stimulation of hypothalamic defense area(HDA) were used, and mean arterial pressure(MAP) and heart rate were measured.Results: GABA uptake inhibitor nipecotic acid-induced increase of MAP was blocked by GABAA receptor antagonist bicuculline, but not by GABAB antagonist CGP 35348; glutamate could only partially reverse muscimol-induced elevation of BP while showed no obvious effect on GABAB receptor excitant-induced elevation of BP; and microinjection of bicuculline into NTS could block stimulation of HDA-induced pressor response, but CGP 35348 could not. Conclusion: The differences between GABAA and GABAB receptors in the regulation of cardiovascular activity in NTS may be due to the presynaptic distribution of GABAB receptors and postsynaptic exsistence of GABAA receptors in NTS. |
| Key words: nucleus tractus solitarius receptors, γ-aminobutyric acid hypothalamic defence area blood pressure |
