侧脑室注射心房钠尿肽对大鼠室旁核单位放电...

We have applied microelectrode technique to record 118 spontaneously firing units from the hypothalamus in rats. Detection of the recording sites showed that 84 were in the paraventricular nucleus (PVN) and 34 were near the PVN (near-PVN). After intracerebroventricular (i.c.v.) administration of atrial natriuretic polypeptide (ANP), 91% (P less than 0.005) of the PVN neurones and 71% (P greater than 0.05) of near-PVN neurones sensitive to ANP showed a significant decrease in spontaneously firing rate. After i.c.v. administration of hypertonic NaCl solution, 64.7% (P less than 0.005) of the PVN neurones and 61.1% (P greater than 0.05) of near-PVN neurones showed a significant increase in firing rate. The results indicate that i.c.v. administration of ANP profoundly inhibits the electrical activity of the PVN neurones, but hypertonic NaCl solution markedly stimulates the PVN neurones.     

侧脑室注入心钠素对清醒大鼠高渗氯化钠诱发的加压素释放的影响

本实验利用放射免疫分析方法观察了侧脑室注入心钠素(ANF)对清醒大鼠高渗NaCl诱发的精氨酸加压素(AVP)释放的影响。结果表明,侧脑室注入高渗NaCl有明显刺激AVP释放的作用,ANP的预处理对高渗NaCl诱发的AVP释放则具有明显的抑制作用。ANF对AVP的基础释放无明显影响。这提示ANF在脑内可能作为一种神经递质或神经调制物影响渗透性AVP释放。     

侧脑室注射心房钠尿肽对大鼠室旁核单位放电的影响

本实验利用微电极技术在大鼠下丘脑共记录到118个自发放电单位,其中84个位于室旁核(PVN)内,34个位于 PVN 邻近部位。侧脑室注入心房钠尿肽(ANP)后,受其影响的 PVN神经元和 PVN 邻近部位神经元,分别有91%(P<0.005)和71%(P>0.05)表现为自发放电频率减少;侧脑室注入高渗 NaCl 溶液则分别使64.7%(P<0.005)和61.1%(P>0.05)的神经元自发放电频率增加。结果表明,侧脑室注入 ANP 对 PVN 神经元自发放电活动具有明显的抑制作用。     

心房钠尿肽对血管紧张素及禁水引起大鼠饮水行为的影响

利用T-迷宫,以S-D大鼠在直跑道内的钦水跑速及大鼠在饲养笼内的饮水量作为指标,观察ANP对AugⅡ及禁水引起大鼠饮水行为的影响。结果显示,通过脑室导管将100ng AngⅡ注入第三脑室后,立即引起已饱水大鼠快速奔跑的饮水行为。iCV.注射2μgANP3min后,再注射AngⅡ,大鼠即失去快速奔跑饮水行为。禁水24h后,大鼠放入迷宫内亦出现快速奔跑饮水行为,icv.注射ANP 3min及20min时,跑速明显减慢。观察同组实验动物的饮水量变化,与跑速比较,两者变化方向和程度基本一致。本实验证明,ANP可以使AngⅡ或禁水致渴的大鼠饮水动机减低,跑速减慢,饮水量减少。由此可见,ANP不仅具有利钠、利尿、降低血压作用,还可以影响神经性致渴机制,抑制饮水行为,是机体维持体液平衡的重要调节物。