慢性缺氧大鼠右心房的超微病理变化及血浆ANF含量改变的实验研究

目的：研究慢性间断性缺氧时右心房心肌细胞的病理改变及血浆、右心房心房利钠因子（ＡＮＦ）含量的变化规律。方法：利用电镜观察模拟海拔５０００ｍ高度缺氧条件下不同时期大鼠右心房的超微病理改变，同时利用免疫组织化学方法检测右心房ＡＮＦ含量的改变，并利用放射免疫方法测定慢性间断性缺氧大鼠血浆ＡＮＦ含量的变化规律。结果：慢性间断性缺氧时，右心房心肌细胞及间质具有多种超微病理改变，右心房组织ＡＮＦ含量下降，血浆     

心包剥离术对老年慢性缩窄性心包炎心钠素与内皮素变化影响的多中心研究

目的：探讨心包剥离术对老年慢性缩窄性心包炎心钠素与内皮素变化的影响。方法：收集我院收治的慢性缩窄性心包炎患者66例,随机分为对照组和实验组,每组各33例,患者均给予相应治疗,对照组给予相应强心、扩血管药物,实验组患者行心包剥离术,治疗结束后,对所有患者的ANF、ET、血压以及临床治疗效果进行检测并比较。结果,与治疗前相比,治疗后两组患者ANF、ET、舒张压以及脉压水平均下降,收缩压水平升高(P<0.05);与对照组相比,实验组患者ANF、ET、舒张压以及脉压水平较低,收缩压水平较高(P<0.05);实验组患者治疗总有效率较高(P<0.05)。结论：心包剥离术能够降低慢性缩窄性心包炎患者ANF、ET、舒张压以及脉压水平,升高收缩压水平,临床疗效较好,对临床有指导意义。     

大鼠脑内心钠素的免疫组织化学观察

本文用兔抗心钠素Ⅲ特异血清,用ABC法观察了大鼠脑内心钠素的分布。结果表明心钠素在脑内广泛存在。密集的心钠素免疫反应阳性神经元,主要见于下丘脑视前区、室周核及下丘脑前核等处。密集的心钠素免疫反应阳性纤维布于下丘脑室旁核,终纹床核及终板血管器官等处。心钠素在脑内的分布状态提示心纳素可能具有中枢性调节水电解质平衡及心、血管的功能,此外,亦可能参与下丘脑—垂体系神经内分泌调节的作用。     

Atrial natriuretic factor (ANF 103–126) enhances volume- and pressor-induced heart rate response in the conscious rat

The reduction in blood pressure due to ANF(103–126) fails to elicit reflex cardioacceleration in the conscious rat. To examine baroreflex sensitivity, the effect of ANF(103–126) on the heart period (HP) response to rapid central volume expansion and to alterations in mean arterial pressure (MAP) induced by bolus injections of phenylephrine and sodium nitroprusside was assessed. ANF(103–126) significantly augmented the bradycardic response induced by acute volume expansion from 426 ± 21 to 391 ± 23 beats min^-1 versus 421 ± 23 to 405 ± 24 without ANF(103–126). Baroreflex sensitivity was defined by the ratio of the change in heart period to the maximal change in mean arterial pressure. The dose of ANF(103–126) utilized did not affect basal heart rate or the magnitude of the mean arterial pressure response to phenylephrine but did significantly enhance the nitroprusside-induced decrease in mean arterial pressure. Baroreceptor sensitivity to phenylephrine was significantly increased by ANF(103–126): 0.997 ± 0.07 (ms mmHg^-1) during ANF(103–126) vs 0.613 ± 0.08 during vehicle. The total duration of the heart rate response to phenylephrine was also prolonged. In contrast, ANF(103–126) did not alter the baroreceptor sensitivity (1.45 ± 0.3 vs 1.43 ± 0.2 ms mmHg^-1) or duration of heart rate response to nitroprusside. In the conscious rat, ANF(103–126) modifies the heart rate response to changes in mean arterial pressure and acute central volume expansion. This action appears to be dependent on stimulation of cardiac vagal afferents.     

The relationship between atrial pressure, atrial dimensions and atrial natriuretic factor during pacing tachycardia in dogs

Acute supraventricular tachycardia is known to increase the plasma level of atrial natriuretic factor (ANF). The purpose of these experiments was to investigate if such an increase in plasma-ANF could be ascribed to changes in atrial pressure and atrial dimensions. Eight anaesthetized dogs were instrumented with atrial pressure catheters and sonomicrometers to measure left and right auricular and atrial free wall dimensions. An acute increase in atrial rate from 150 to 200 min-1 for 10 min did not change plasma-ANF or atrial haemodynamic variables. A further increase in atrial rate to 250 or 300 min-1 increased right and left atrial intracavitary pressures (P less than 0.01), both auricular diameters and right atrial free wall segment length (P less than 0.05). Left atrial free wall segment length remained unchanged. Plasma-ANF increased in all dogs (P less than 0.01). The change in plasma-ANF correlated well with changes in atrial pressures as well as with changes in atrial dimensions. These results support the hypothesis that release of ANF during acute atrial tachycardia may in part be attributed to atrial dilatation.     

Synthesis and biological activity profiles of atrial natriuretic factor (ANF) analogs

Several analogs of the atrial natriuretic factor (ANF) were synthesized by the solid-phase method using the acetamidomethyl (Acm) group for sulfhydryl protection. The compounds were tested in a receptor binding assay using bovine adrenal zona glomerulosa cell membranes and in the rat diuresis/natriuresis assay. Substitution of tyrosine in position 116 of ANF(101–126) and of the analog [3-Mpr¹⁰⁵]ANF(105–126)(3-Mpr = 3-mercaptopropionic acid) did not alter the biological activity profiles and, therefore, these two analogs in radioiodinated form will be useful for enzymatic degradation and clearance studies. Replacement of 3-mercaptopropionic acid with 2-mercaptopropionic acid in [3-Mpr¹⁰⁵]ANF(105–126) resulted in an analog with very low potency in both assay systems, presumably as a consequence of the steric bulk and/or local conformational restriction produced by the methyl group attached to the α-carbon in position 105. The analog [3-Mpr¹⁰⁵, Nva¹⁰⁹]ANF(105–126)(Nva = norvaline) showed very low affinity in the receptor binding assay but displayed considerable diuretic/natriuretic activity. The obtained biological activity profiles suggest that in comparison with other ANF peptides the des-amino ANF(105–126) analogs may have a somewhat longer half-life in vivo or, alternatively, may indicate a more complex situation of ANF receptor or binding site heterogeneity.     

益肺康心胶囊对大鼠肺心病模型血浆内皮素、一氧化氮、心钠素的影响

目的探讨益肺康心胶囊对大鼠肺心病模型血浆内皮素（ET）、一氧化氮（NO）、心钠素（ANF）的影响。方法将40只雄性wistar大鼠随机分为空白组、模型组、治疗组、对照组,每组10只。治疗组口服益肺康心胶囊;对照组口服硝苯地平,疗程为15d。取静脉血检测大鼠血浆ET、NO、ANF水平。结果益肺康心胶囊可明显降低肺心病大鼠血浆ET及ANF水平,同时还能显著升高NO水平,与模型组比较有显著差异。结论益肺康心胶囊可降低肺心病大鼠血浆ET及ANF水平,同时能升高NO水平。     

心钠素mRNA在心肌肥厚大鼠心脏中的表达

目的:检测心钠素(atrial natriuretic factor,ANF)mRNA在心肌肥厚大鼠心肌中的表达.方法:实验组以手术缩窄大鼠腹主动脉致心肌肥厚,对照为假手术组;应用竞争聚合酶链式反应(PCR)方法检测两组左心室ANF mRNA表达差异.结果:与假手术组相比,手术组术后心肌中ANF mRNA表达增高(P＜0.05),并随时间增加而增高.结论:ANF mRNA在心肌肥厚大鼠心脏表达增加.