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Characteristics of a novel vasopressin receptor in the cardiovascular system

心血管系统中新型加压素受体的特征

基本信息

批准号：
08672631
负责人：
TAKANO Yukio
金额：
$ 1.34万
依托单位：
Fukuoka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08672631/
关键词：
Vasopressin Vasopressin receptor nucleus tractus solitarius area postrema V1a receptor mRNA arterial baroreceptor reflex V2 receptor mRNA 循環調節 VI受容体循環器作用海馬受容体拮抗薬

项目摘要

1. Vasopressin (AVP) receptor subtypes in rat brain :High-affibity [_3H]-AVP binding sites have been identified in both the nucleus tractus solitarius (NTS) and the area postrema (AP). In addition, we examined the subtype (s) of the AVP receptor in the NTS and the AP.The binding study showed that AVP receptor in these areas is the V1 subtype. Next, we tested for AVP A1a-and V20receptor mRNAs in the NTS and AP of adult rats. PCR product of the V1a and V2 receptor mRNA was detected in the NTS,but not in the AP.We do not know why V1a receptor mRNA was not detected in the Apa in this study. Possible explanations are that the sequence of the AVP receptor mRNA in the brain may not completely consistent with that of V1a receptor mRNA in peripheral tissues.2. Roles of AVP receptors in cardiovascular regulation :The role of AVP in regulation of the baroreceptor reflex in the AP was examined in anesthetized hypertensive rats. The sensitivity of the baroreceptor reflex in a one-kidney one clip (1 … More K1C) hypertensive rats was increased in only the initial stage (2 weeks), in association with increase in blood pressure, and then returned to the normal level. This increase in the sensitivity of the baroreceptor reflex in the initial stage was reversed by microinjection of a V1 or V2 antagonist into the AP.AVP V2 receptor mRNA was expressed temporarily in the AP in this period.3. Electrophysiological studies :We found the functional relationship between the area postrema and NTS in the physiological experiments in vitro. Stimulating electrodes were set on the AP and/or solitary tract (ST), and spikes were recorded from the NTS neuron. Most of neurons in the AP and NTS showed spontaneous firings, and some of neurons in the NTS received the neuronal inputs from both the AP and ST.AVP caused inhibitory (24.3%) and excitatory efects (24.7%) on sponteous firings of the of the AP neurons. The rest of neurons (51.3%) were no effect. These results suggest that there are two types of AVP sensitive neuron and that the AP neurons responding to the endogenous AVP send the information into the NTS neurons and modify arterial baroreceptor reflex. Less

1.大鼠脑内加压素（AVP）受体亚型：孤束核（NTS）和最后区（AP）均存在[_3H]-AVP高亲和力结合位点。此外，我们还检测了孤束核和腹主动脉的AVP受体亚型，结合研究表明孤束核和腹主动脉的AVP受体均为V1亚型。接下来，我们检测了成年大鼠NTS和AP中AVP A1 a和V20受体的mRNA。在NTS中检测到V1 a和V2受体mRNA的PCR产物，而在AP中未检测到，我们不知道为什么在本研究的阿帕中未检测到V1 a受体mRNA。可能的解释是脑内AVP受体mRNA的序列与外周组织中V1 a受体mRNA的序列可能不完全一致. AVP受体在心血管调节中的作用：在麻醉的高血压大鼠中检查AVP在AP中的压力感受性反射的调节中的作用。一肾一夹压力感受性反射的敏感性（1 ...更多信息 K1 C）高血压大鼠仅在初始阶段（2周）升高，与血压升高相关，然后恢复至正常水平。AP内微量注射V1或V2拮抗剂可逆转压力感受性反射敏感性的增加，此时AP内暂时表达AVP V2受体mRNA.电生理学研究：在离体生理实验中发现了最后区与孤束核之间的功能联系。在AP和/或孤束（ST）上设置刺激电极，记录NTS神经元的棘波。AP和NTS的神经元大多数为自发放电，NTS的部分神经元同时接受AP和ST的神经元输入，AVP对AP神经元的自发放电有抑制（24.3%）和兴奋（24.7%）作用。其余神经元（51.3%）无作用。这些结果提示，孤束核存在两种AVP敏感神经元，AP神经元对内源性AVP产生反应，并将信息传递到孤束核神经元，改变孤束核压力感受性反射。少