自发性高血压大鼠中枢去甲肾上腺素与血管紧张...

The norepinephrine (NE) and angiotensin II (A II) contents in the brain regions of SHR and WKY (Wistar Kyoto) rats at different ages were determined by fluorospectrophotometry and radioimmunoassay. The systolic blood pressure (SBP) of the rats was measured indirectly with a tail cuff technique in conscious state. The results were as follows: There was no significant difference in the central A II and NE contents between SHR and WKY rats at 8-week age. Since 12th week age the SBP of SHR has increased gradually, up to 16th to 20th week and then maintained steady level. Whereas there was no significant change of SBP in WKY rats in the same span of age. In the early and late states of hypertension the A II contents in the medulla oblongata, pons, hypothalamus and nucleus caudatus of SHR were markedly higher than those of the age-matched WKY rats. But the change of NE content of SHR in the early stage showed a different picture as compared with that of WKY rats, i.e., NE decreased in medulla oblongata and anterior hypothalamus but increased in pons, posterior hypothalamus and nucleus caudatus. However, in the late stage there was no such significant difference between SHR and WKY rats. Consequently, it is suggested that the central A II and NE participated in the development of hypertension of SHR, and that the maintenance of hypertension is mainly dependent upon the increased A II content. Microinjection of captopril or 6-OHDA in the lateral cerebroventricle of SHR elicited a decrease of BP and reduction of both A II and NE contents in the medulla and hypothalamus.(ABSTRACT TRUNCATED AT 250 WORDS)     

Aortic stiffness and pulse pressure amplification in Wistar-Kyoto and spontaneously hypertensive rats

In humans, increased body weight and arterial stiffness are significantly associated, independently of blood pressure (BP) level. The finding was never investigated in rodents devoid of metabolic disorders as spontaneously hypertensive rats (SHR). Using simultaneous catheterization of proximal and distal aorta, we measured body weight, intra-arterial BP, heart rate and their variability (spectral analysis), aortic pulse wave velocity (PWV), and systolic and pulse pressure (PP) amplifications in unrestrained conscious Wistar-Kyoto (WKY) rats and SHR between 6 and 24 wk of age. Aortic proximal systolic and diastolic pressure, PP, and mean BP were significantly higher in SHR than in WKY rats and increased significantly with age (with the exception of PP). PP amplification increased with age but did not differ between strains. PWV was significantly associated with heart rate variability. PWV was significantly higher (via two-way variance analysis) in SHR than in WKY rats (strain effect) and increased markedly with age in both strains (age effect). Adjustment of PWV to mean BP attenuated markedly both the age and the strain effects. After adjustment for body weight, either alone or associated with mean BP, the age effect was not more significant, but the strain effect was markedly enhanced. In conscious unanesthetized SHR and WKY rats, aortic stiffness is consistently associated with body weight independent of age and mean BP. An intervention study should consider in the objectives systolic BP and PP amplifications measured in conscious animals, central control of body weight, and autonomic nervous system.     

原发性高血压患者红细胞抗高血压因子对高血压...

The effects of antihypertensive factor (AHF) from erythrocytes of essential hypertensive human subjects on the systolic blood pressure (SBP) and diastolic blood pressure (DBP) in spontaneously hypertensive rats (SHR), renal hypertensive rats (RHR), Wistar-Kyoto rats (WKY) and Wistar rats were examined. Single intraperitoneal injection of AHF (1.6 mg/kg body weight) resulted in a significant decrease in SBP of SHR and RHR. At 10 min postinjection, AHF lowered the SBP in SHR by 34.0 mmHg. SBP recovered to the original level at 3 h. The maximal decrease of SBP in RHR by 92.5 mmHg was at 24h postadministration and the SBP did not recover until the 9th day. When AHF was administered via femoral vein (0.8 mg/kg body weight), the maximal decrease values of the SBP and the DBP were 42.8 and 48.2 mmHg in SHR at 12 min and 38.3 and 42.5 mmHg in RHR at 25 min postinjection respectively. The DBP in Wistar rats decreased considerably (from 96.7 +/- 12.9 to 83.3 +/- 11.7 mmHg) at 5 min postadministration of AHF, but no effect on DBP in WKY rats was observed. The depressor effect of AHF on SBP in RHR was dose-dependent. AHF could also antagonize the pressor effect of norepinephrine in Wistar rats.     

Noradrenergic content and turnover rate in kidney and heart shows gender and strain differences.

The objective of this study was to compare strain and gender differences in kidney and heart norepinephrine (NE) content and turnover rate in normotensive Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR, SHR/a, and SHR/y). Our laboratory has shown that the Y chromosome has a significant effect on blood pressure in the SHR model of hypertension through the use of two new rat stains, SHR/a and SHR/y, to study the Y chromosome. SHR/a have a SHR autosomal genetic background with a WKY Y chromosome, whereas the SHR/y rats have a WKY autosomal genetic background with a SHR Y chromosome. Tissues were homogenized after alpha-methyl-DL-p-tyrosine injection and analyzed for NE. The male kidney NE content was significantly lower in the WKY compared with the SHR, SHR/y, and SHR/a. Kidney and heart NE content was significantly higher in females compared with males in all strains except the SHR/y. The WKY and SHR/y females had significantly lower kidney NE turnover rates, and the SHR and SHR/a females had significantly higher kidney NE turnover rates than strain-matched males. This study suggests both a strain and gender difference in sympathetic nervous system activity through noradrenergic neurotransmission.     

Comparison of circadian rhythm characteristics of blood pressure and heart rate in patients before and after elective coronary artery bypass surgery

Coronary artery bypass grafting surgery (CABGS) is done to reperfuse the ischemic myocardium of coronary disease patients. This study was designed to analyze the circadian rhythm characteristics of blood pressure (BP) and heart rate (HR) of patients before and after CABGS. Fifty-one patients undergoing elective CABGS were studied; 21 patients received one, 12 two and 18 three or more grafts. BP was monitored for 24h before and after CABGS while patients were recumbent in the hospital. Systolic (S) and diastolic (D) BP and HR were assessed every 30 min. Of the 51 patients, 37 (73%) had nondipper 24h BP patterns (nocturnal decline in BP < 10% of daytime mean level) in the preoperative baseline assessment. The peak and MESOR (rhythm-adjusted 24h mean) values of the circadian rhythm in SBP, DBP, and pulse pressure (PP) significantly declined following surgery, while HR and rate-pressure product (RPP = SBP x HR) markedly increased. The double amplitude (peak-to-trough variation) of the circadian rhythm in SBP and DBP was significantly reduced postoperatively, and that of the rhythm in HR and RPP significantly increased. The slopes of the morning rise and evening dip in the 24h SBP profile were reduced significantly after bypass grafting. The corresponding slopes of the HR profile, in contrast, were markedly increased.     

Antihypertensive effects of I-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine on plasma renin activity and catecholamine responses in spontaneously hypertensive rats

Fourteen 23 week old male spontaneously hypertensive rats (SHR) were randomly divided into saline control or phospholipid (I-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine) treatment groups. Four weeks of baseline systolic blood pressure (SBP) and heart rate (HR) measurements were determined via tail plethysmography. On week 25 of the baseline period a 1.5 ml blood sample was taken by tail clip for analysis of norepinephrine (NE), epinephrine (E), and plasma renin activity (PRA). On the following week, a single injection of phospholipid (11 ug/kg, s.c.) was given to the experimental animals following baseline SBP and HR determinations. A similar procedure was employed for control subjects, except they received an injection of normal saline (0.5 ml, s.c.). Systolic BP and HR responses were monitored for 24 minutes following the injection. A 1.5 ml blood sample was taken at the end of the 4th minute for NE, E, and PRA assays. A significant drop in SBP (202 +/- 5 mmHg to 124 +/- 6 mmHg) and an increase in HR (431 +/- 17 bpm to 519 +/- 21 bpm) were observed for experimental animals, but not for control subjects. Plasma NE increased significantly (446 +/- 42 pg/ml to 1099 +/- 77 pg/ml), but E remained unchanged following treatment with the phospholipid. Plasma renin activity increased for both groups, but this change was only significant for the experimental group (18.1 +/- 5.7 ng Al/ml/hr to 34.3 +/- 3.6 ng Al/ml/hr). Thus, it appears that I-hexadecyl-2-acetyl-sn-glycero-3-phosphocholine is a potent antihypertensive vasodilating agent which stimulates baroreceptor mediated sympathetic discharge to the heart and kidneys of the SHR.     

Development of arterial pressure rhythm and cardiac contraction rate and effects of beta-adrenomimetic agents]

Blood pressure (BP) and heart rate (HR) rhythms were studied in premature infants (299 profiles ranged 24-106 h at 20--min intervals) and 11-13-year-old children (19 profiles for 48 h at 15-min intervals) to explore ultradian-to-circannual rhythm characteristics in BP and HR in preterm human infant and to elucidate the influence of antenatal betamimetic (BM) exposure on adolescent BP and HR rhythms. A circannual modulation of the 3-h amplitude (A) or MESOR of systolic BP (SBP) and diastolic BP (DBP) was seen mainly in prematures with a positive family history of high BP on the father's (f+) side or with both a patro linous and matro-linous history (f+m+), the circannual modulation of HR ultradian A was statistically significant only in "f- m-" infants. In urine collected at 3 h intervals for 24-h spans from 21 premature infants Na+,K+ and 11-oxycorticosteroids had a significant circadian rhythm. 9 adolescents (BM+), which were exposed in utero to different BM doses, had a significantly higher SBP and DBP MESOR and numerically higher circadian A as compared to 10 controls (BM-); correlation (P less than 0.05) between BM dose and HR circadian A was found. DBP led SBP in 8 or 10 "BM-" but in 4 of 9 "BM+" (acrophase difference 17 min and 3 min correspondingly).(ABSTRACT TRUNCATED AT 250 WORDS)     

Alterations in plasma catecholamines and behavior during acute stress in spontaneously hypertensive and Wistar-Kyoto normotensive rats

The responsiveness of the sympathoadrenal system to stress was assessed in spontaneously hypertensive (SHR) and Wistar-Kyoto normotensive (WKY) rats at 6, 18, and 48 weeks of age. Two days after insertion of a tail arterial catheter, each rat was transferred from its home cage to a shock chamber, and after 5 min received 60 footshocks over a 5 min interval. Blood samples were taken from undisturbed rats when in the home cage, 3–5 min after transfer to the shock chamber, and at the end of shock. An additional group of naive SHR and WKY rats was exposed to footshock and behavioral responses were recorded. There were no strain differences in levels of norepinephrine (NE) or epinephrine (EPI) while rats were undisturbed in their home cages. Transfer to the shock chamber resulted in a greater increase in plasma levels of both catecholamines in SHRs of each age. A similar pattern was evident after footshock; SHR rats had significantly higher post-shock levels of plasma NE and EPI than age-matched WKY rats. During shock, SHR rats were more active and jumped and reared more frequently than WKYs. These results demonstrate that the sympathoadrenal system of SHR rats is more responsive than normotensive rats to stressful stimuli and that this hyper-responsitivity is independent of increases in blood pressure. The excessive discharge of NE and EPI into plasma during stress may contribute to the development and maintenance of high blood pressure in SHR rats.     

The Correlation Between Activity,Blood Pressure and Heart Rate in Freely Mobile Sprague-Dawley and Transgenic Rats

Systolic (SBP) and diastolic blood pressure (DBP), heart rate (HR) and locomotor activity have been measured at 1-min intervals for 24 h in Sprague-Dawley (N = 5) and for 2x24 h in transgenic hypertensive (N = 4) rats. The animals were freely mobile and entrained to a 12:12 LD cycle (lights on at 0700). The endogenous circadian component of the cardiovascular variables was removed from the raw data, and then correlations between activity and the residual component (raw data minus the endogenous component) of SBP, DBP and HR were calculated. This calculation was performed twice, in the mid-light and mid-dark phases. We have investigated if the mean size of the correlation coefficients depended on cardiovascular variable (SBP, DBP or HR), phase (D or L) or strain (Sprague-Dawley, SPD, or Transgenic, TG, rats). Nearly all correlations were positive and ANOVA's showed a significant effect of cardiovascular variable for both strains, with correlations for HR being significantly higher than those for SBP and DBP. The mean correlations in the SPD strain were significantly higher than in the TG strain for variables SBP and DBP, but not for HR. The correlations between activity and blood pressure were more marked for SPD rats in the light (inactive) than dark (active) phase. Both strains showed ultradian rhythms in all variables, particularly in the light phase. If the analysis was repeated using deviations of the cardiovascular variables from a 1-h moving average rather than the endogenous circadian component, then the results were very similar. The results are discussed in terms of the links between the rhythms of activity and cardiovascular variables, with particular reference to differences between the two strains.     

SHR Y chromosome enhances the nocturnal blood pressure in socially interacting rats

Our objective was to test the hypothesis that nocturnal mean arterial pressure (MAP), heart rate (HR), and activity would be increased in 1) colony over individually caged rats and 2) the spontaneously hypertensive rat (SHR) Y chromosome strain (SHR/y colony) compared with Wistar-Kyoto (WKY) rats. MAP, HR, and activity were monitored using radiotelemetry. The nocturnal MAP rise expressed as the percentage change in MAP from light to dark was increased (P < 0.05) in the SHR/y colony. The SHR Y chromosome increased MAP in both the colony and caged groups compared with WKY (P < 0.001). The SHR/y colony animals spent 23% of a 24-h period at a MAP >120 mmHg, whereas the WKY colony animals spent 2% of a 24-h period in this range. The MAP of the SHR/y colony on clonidine was reduced (P < 0.001) to WKY baseline values. Activity but not HR was increased (P < 0.01) in the WKY and SHR/y colonies compared with caged animals. In conclusion, colony housing and the SHR Y chromosome increased MAP compared with individually caged housing.     

Gender Dependency of Circadian Blood Pressure and Heart Rate Profiles in Spontaneously Hypertensive Rats: Effects of Beta‐Blockers

This study investigated (i) blood pressure (BP), heart rate (HR), and their relation to urinary NOx and eNOS protein expression in male and female spontaneously hypertensive rats (SHR), as well as (ii) gender‐dependent cardiovascular effects of nebivolol (NEB) in comparison to metoprolol (MET) in SHR. BP and HR were measured telemetrically after a single intraperitoneal application of NEB or MET at 07.00 and 19.00 h in male rats and at 19.00 h in proestrus female rats. The two β‐blockers varied in time of decreasing BP and HR and also in duration. In males, MET decreased BP and HR for few hours exclusively when applied at the onset of the activity phase (i.e., at 19.00 h), while after its application at 07.00 h, BP and HR were unchanged. In females, MET also caused a short‐lasting BP and HR reduction, with the effect being more pronounced than in males. In males, NEB at either dosing time decreased HR and BP to a greater extent than did MET. This effect was evident both during the activity and rest periods and persisted for at least five days. In females, NEB provoked a similar, but more pronounced, effect on BP and HR in comparison to males. These findings demonstrate that significant gender‐dependent differences in the circadian profile of BP and HR exist. BP and urinary NOx as well as eNOS expression are inversely correlated, and the cardiovascular effects of NEB and MET vary, depending on the time of application as well as gender.     

Increases in CSF [Na+] precede the increases in blood pressure in Dahl S rats and SHR on a high-salt diet

In Dahl salt-sensitive (S) and salt-resistant (R) rats, and spontaneously hypertensive rats (SHR) and Wistar-Kyoto (WKY) rats, at 5-6 wk of age, a cannula was placed in the cisterna magna, and cerebrospinal fluid (CSF) was withdrawn continuously at 75 microl/12 h. CSF was collected as day- and nighttime samples from rats on a regular salt intake (0.6% Na+; R-Na) and then on a high salt intake (8% Na+; H-Na). In separate groups of rats, the abdominal aorta was cannulated and blood pressure (BP) and heart rate (HR) measured at 10 AM and 10 PM, with rats first on R-Na and then on H-Na. On H-Na, CSF [Na+] started to increase in the daytime of day 2 in Dahl S rats and of day 3 in SHR. BP and HR did not rise until day 3 in Dahl S rats and day 4 in SHR. In Dahl R and WKY rats, high salt did not change CSF [Na+], BP, or HR. In a third set of Dahl S rats, sampling of both CSF and BP was performed in each individual rat. Again, significant increases in CSF [Na+] were observed 1-2 days earlier than the increases in BP and HR. In a fourth set of Dahl S rats, BP and HR were recorded continuously by means of radiotelemetry for 5 days on R-Na and 8 days on H-Na. On H-Na, BP (but not HR) increased first in the nighttime of day 2. In another set of Dahl S rats, intracerebroventricular infusion of antibody Fab fragments binding ouabain-like compounds (OLC) with high affinity prevented the increase in BP and HR by H-Na but further increased CSF [Na+]. Finally, in Wistar rats on H-Na, intracerebroventricular infusion of ouabain increased BP and HR but decreased CSF [Na+]. Thus, in both Dahl S and SHR on H-Na, increases in CSF [Na+] preceded the increases in BP and HR, consistent with a primary role of increased CSF [Na+] in the salt-induced hypertension. An increase in brain OLC in response to the initial increase in CSF [Na+] appears to attenuate further increases in CSF [Na+] but at the "expense" of sympathoexcitation and hypertension.     

Circadian pattern of blood pressure,heart rate,and double product in liver glycogen storage disease

The objective of this study was to determine systolic, diastolic, and mean arterial blood pressure (SBP, DBP, and MAP), heart rate (HR), double-product (DP: SBP x HR), and activity levels and their 24h pattern in liver glycogen storage disease (LGSD) patients. A case series of 12 (11 pediatric and one adult) diurnally active LGSD (seven type I, three type III, and two type IX) subjects were simultaneously assessed by 24h ambulatory blood pressure monitoring and wrist actigraphy. Nine subjects were judged to be hypertensive based on the criterion of an elevated 24h mean SBP and/or DBP being elevated beyond reference standards or the SBP and/or DBP load (percentage of time BP exceeds normal values) being greater than 25%. Two of the three other subjects, not viewed as hypertensive based on their 24h average SBP or DBP, exhibited daytime or nighttime SBP and/or DBP load hypertension. Each study variables displayed statistically significant (p < 0.001) group circadian rhythmicity. The SBP, DBP, and MAP displayed comparable 24h patterns of appreciable amplitude (total peak-trough variation equal to 17.7, 23.6, and 19.6%, respectively, of the 24h mean) with highest values (orthophase) occurring approximately 11 h after the commencement of daytime activity. The sleep-time trough (bathyphase) occurred approximately 4.5 h before morning awakening. The statistically significant (p < 0.006) circadian rhythms of HR (amplitude equal to 33.2% of the 24h mean) and DP (amplitude equal to 49.4% of the 24h mean) peaked earlier, approximately 7.4 h into the daytime activity span. The sleep-time trough occurred approximately 3 h before morning awakening. The 24h pattern in the cardiovascular variables was correlated with the 24h pattern of activity, with r ranging from 0.50 for DBP to 0.39 for HR.     

Body fluids and plasma atrial peptide after its chronic infusion in hypertensive rats

To determine the role of body fluid volume in the chronic hypotensive effect of atrial natriuretic factor (ANF), spontaneously hypertensive (SHR) and Wistar-Kyoto (WKY) rats were infused with the peptide (Arg 101-Tyr 126) at a rate of 100 ng/h/rat for 5 days. Blood pressure (BP) was decreased from 176 +/- 4 to 133 +/- 3 mmHg in the SHR group 4 days after ANF infusion was initiated, whereas no changes were observed in ANF-infused WKY animals. Starting 5 days after the infusion began, body fluid measurements revealed no differences in plasma, blood and extracellular fluid volumes or in interstitial spaces. BP and plasma ANF concentrations were determined in another set of experiments before, during and after chronic ANF infusion. BP declined from 169 +/- 3 to 133 +/- 5 mmHg in SHR 5 days after the infusion commenced, but returned to basal values by day 10 or 11. Plasma ANF was significantly higher in SHR than in WKY rats throughout the observation period. However, there were no discernible changes in this parameter in ANF-infused SHR compared to non-infused SHR. A 3-fold rise in plasma ANF was noted in infused WKY rats at day 3 only. It is concluded that the chronic hypotensive effect of ANF in hypertensive animals is not related to changes in either body fluid volume or distribution. Moreover, the finding that chronic ANF infusion reduces BP in SHR without altering its plasma levels suggests a rapid ANF turnover.     

Effect of blood pressure on L-NAME-sensitive component of vasorelaxation in adult rats

The aim of this study was to investigate nitric oxide (NO) production and L-NAME-sensitive component of endothelium-dependent vasorelaxation in adult normotensive Wistar-Kyoto rats (WKY), borderline hypertensive rats (BHR) and spontaneously hypertensive rats (SHR). Blood pressure (BP) of WKY, BHR and SHR (determined by tail-cuff) was 111+/-3, 140+/-4 and 184+/-6 mm Hg, respectively. NO synthase activity (determined by conversion of [(3)H]-L-arginine) was significantly higher in the aorta of BHR and SHR vs. WKY and in the left ventricle of SHR vs. both BHR and WKY. L-NAME-sensitive component of endothelium-dependent relaxation was investigated in the preconstricted femoral arteries using the wire myograph during isometric conditions as a difference between acetylcholine-induced relaxation before and after acute N(G)-nitro-L-arginine methyl ester pre-treatment (L-NAME, 10(-5) mol/l). Acetylcholine-induced vasorelaxation of SHR was significantly greater than that in WKY. L-NAME-sensitive component of vasorelaxation in WKY, BHR and SHR was 20+/-3 %, 29+/-4 % (p<0.05 vs. WKY) and 37+/-3 % (p<0.05 vs. BHR), respectively. There was a significant positive correlation between BP and L-NAME-sensitive component of relaxation of the femoral artery. In conclusion, results suggest the absence of endothelial dysfunction in the femoral artery of adult borderline and spontaneously hypertensive rats and gradual elevation of L-NAME-sensitive component of vasorelaxation with increasing blood pressure.     

Sensitivity of Heart Rate and Blood Pressure to Spontaneous Activity in Transgenic Rats

Spontaneous changes in heart rate (HR), activity and systolic (SBP) and diastolic (DBP) blood pressure have been measured in 3 groups of 7 transgenic [TGR(mRen-2)27] rats for 4 weeks, starting at 12 weeks of age, and living on a 12:12 L:D schedule (light on at 07:00 h). Group TG-ENA was given enalapril, an angiotensin-converting enzyme inhibitor, in its drinking water; group TG-AMLO was given the calcium-channel blocker, amlodipine, by the same route; and group TG-VEH had no addition to its drinking water and so acted as a control. The sensitivity of the cardiovascular variables (CV's) to spontaneous activity was assessed throughout the study period by measuring the gradient of [CV / activity]. For the control (TG-VEH) group, mean HR was highest during the dark phase, at which time the sensitivity to spontaneous activity was least. By contrast, the circadian rhythms of SBP and DBP were inverted, peaking in the light (resting) phase, and there was no reliable difference between the light and dark phases with regard to the sensitivity of SBP or DBP to the effects of spontaneous activity. Enalapril reduced SBP and DBP, but did not alter their phase inversion with respect to HR. However, in SBP and DBP, as well as HR, sensitivities to spontaneous activity were now greater in the light phase. Amlodipine also reduced SBP and DBP and, in addition, greatly reduced the amplitude of their circadian rhythms. With this treatment also, sensitivity to spontaneous activity was greatest in the light phase for HR, SBP and DBP. A simple explanation of these results is that, in the absence of treatment, transgenic rats of this age have DBP and, particularly, SBP values that are too high in the light (resting) phase to permit much further rise due to spontaneous activity, and that this "ceiling effect" no longer holds if SBP and DBP have been reduced pharmacologically.     

Cold-restraint induced gastric lesions in normotensive and spontaneously hypertensive rats

Spontaneously hypertensive (SHR) rats and normotensive Wistar-Kyoto (WKY) rats were subjected to 2 hr of cold-restraint stress at 2–6°C following a 24 hr fast. WKY rats had a significantly greater incidence and degree of ulceration of the gastric glandular mucosa than did SHR rats. Mean arterial pressure, obtained from a chronic arterial cannula, fell during 2 hr of cold-restraint stress in both SHR and WKY rats. Heart rate was unchanged in WKY but fell significantly in SHR. Plasma norepinephrine (NE) and epinephrine (E), determined by radioenzymatic assay, increased significantly following stress. Increased levels of NE remained similar for both SHR and WKY rats, while post-stress levels of E for the SHR rats greatly exceeded E levels for WKY rats. A greater degree of hypothermia was also noted in SHR rats. Decreased stress induced ulcerogenesis in the SHR may be due to the well-known altered hemodynamic and autonomic nervous system reactivity in this strain or other factors not yet discovered.     

Autoradiographic study of 3H-lysine uptake by superior cervical and stellate ganglia in prehypertensive spontaneously hypertensive rats

In order to compare the functional state of sympathetic ganglia in spontaneously hypertensive (SHR) with those in normotensive Wistar Kyoto rats (WKY), protein synthetic activity was examined by light microscopic autoradiography with 3H-lysine. The number of silver grains over the cytoplasm of ganglion cells in the superior cervical and stellate ganglia of newborn and 30-day-old animals were counted on photographic enlargements. In both sympathetic ganglia there were significantly more silver grains over ganglion cells in SHR compared with age-matched WKY at 15, 60, and 120 min after injection of 3H-lysine. The increased incorporation of the label by both sympathetic ganglia was more marked in newborn than in 30-day-old animals. This result shows that protein synthetic activity in these ganglion cells is increased in SHR from the newborn stage. It is suggested that a congenital hyperfunction of sympathetic ganglia occurs in SHR.     

Ultradian rhythmic models of blood pressure variation in normal human daily life

To examine levels and variance structure of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR), we measured those 3 variables every 7.5 min for 24 h (approximately 192 samples each subject) by ambulatory monitoring in 2 nominated groups of normal volunteers: younger (Y; 8 men, 5 women, 24-44 years) and older (O; 13 men, 12 women, 50-95 years). Y and O did not differ in either sleep or wake means for HR and DBP. Mean SBP in O was 17 mm Hg higher than in Y during wakefulness. Thirty-four subjects had significant low frequency variations (presumably the circadian rhythm) in SBP, DBP and HR, regardless of age. A periodic model fitting the time series required a 9 h feature (rhythm) for Y and O in DBP for best reduction of mean square error. In addition, O regularly showed 3 h features in both SBP and DBP, a 6 h feature in DBP and a 9 h feature in SBP, which were absent in Y. Our results suggest that low-power ultradian rhythms may appear in both SBP and DBP after age 50, and possibly serve as dynamic markers of normal cardiovascular aging.     

正常大鼠植入高血压大鼠肾脏后动脉血压的变化

本实验对12周龄的自发性高血压大鼠(spontaneouslyhypertensiverat,SHR)及其对照组WistarKyoto(WKY)大鼠进行了肾脏移植的研究,并观察受肾移植大鼠动脉血压的变化以及免疫抑制剂对动脉血压的影响。用尾套法对接受同窝另一同胞WKY大鼠肾脏移植且存活5周的6只WKY大鼠(A组)及接受SHR肾脏移植且存活5周的6只WKY大鼠(B组)的尾动脉收缩压进行检测,移植前A、B两组受肾移植大鼠的尾动脉收缩压分别为180±093和183±068kPa,无统计学显著差异(P>005);移植后3、4、5周时,B组大鼠的尾动脉收缩压显著高于A组大鼠,移植后5周时,A,B两组大鼠的收缩压分别为190±071和230±069kPa(P<0001);所用剂量的免疫抑制剂CsA对双侧肾脏完整以及右侧肾脏切除的SHR、WKY大鼠的动脉血压无显著影响。以上结果表明,SHR的肾脏在高血压的形成中可能起重要作用