Biomedical subjects

C Cerutti

Publications and source records attributed to C Cerutti.

50 records · Page 3Linked to original sources

PubMed1989

[The sympathetic and renin-angiotensin systems are complementary in blood pressure regulation].

The consequences of a chronic destruction of sympathetic nerves or of the blockade of the renin angiotensin system (RAS) on the blood pressure (BP) level and its spontaneous variability were studied using a computerized method which allows a continuous monitoring of BP in conscious unrestrained rats. Guanethidine, used to lesion the sympathetic fibres did not alter the BP level but significantly enhanced its variability. On the opposite, angiotensin converting enzyme inhibition decreased the BP level without changing its variability. It is concluded that both systems play a complementary role as the RAS determines the long-term BP level while the sympathetic nerves control its short-term variability in conscious animals.

Animals↗

PubMed1988

Cardiovascular response to emotional stress and spontaneous blood pressure variability in genetically hypertensive rats of the Lyon strain.

1. Intra-aortic blood pressure (BP) was continuously recorded in freely moving genetically hypertensive (LH), normotensive (LN) and low BP (LL) rats of the Lyon strains under basal conditions and during aversive stimulation (a jet of air for 20 min). Rats were studied when 5 and 14 weeks old. 2. The 24 h standard deviation (i.e., variability) of diastolic BP was significantly greater in LH rats of both ages than in LN and LL control rats. 3. In response to the stressor, LH rats showed larger increases in BP than age-matched controls. 4. The BP variability was related to the BP responses to stress in the whole series of rats. 5. It is concluded that the spontaneous BP variability and the BP responses to an experimental stressor rely upon a common regulatory mechanism in rats and that an increased lability of diastolic BP is a primary characteristic of Lyon hypertensive rats.

Aging↗

PubMed1988

Cardiovascular effects of two new calcium antagonists, PY 108-068 and PN 200-110, in conscious spontaneously hypertensive rats.

1. The acute cardiovascular effects of PY 108-068 and PN 200-110 were studied by means of a computerized analysis of the intra-aortic blood pressure (BP) recorded continuously for 26 h in conscious unrestrained spontaneously hypertensive rats. Both compounds were studied at three doses (50, 100 and 200 micrograms kg-1) and each dose was administered intravenously 5 times (09 h 00 min, 14 h 00 min, 19 h 00 min, 24 h 00 min and 09 h 00 min). Baroreflex sensitivity was measured 1 h following the last injection. 2. The two compounds were found to induce rapid (3 min) and dose-dependent falls in BP. After the first administration, these decreases reached -20% and -35% for systolic BP (SBP) and diastolic BP (DBP) respectively with PY 108-068 (200 micrograms kg-1) and -25% and -45% for SBP and DBP respectively with PN 200-110 (200 micrograms kg-1). 3. The duration of the reduction in BP increased with the dose and was much longer for PN 200-110 (180 min for SBP) than for PY 108-068 (20 min for SBP). 4. A tachycardia was associated with the decrease in BP which did not differ at 200 micrograms kg-1 between PY 108-068 (+ 108 beats min-1) and PN 200-110 (+ 103 beats min-1). Baroreflex sensitivity was not significantly increased by either drug. 5. The 5 repeated injections of PY 108-068 and PN 200-110 evoked similar responses. 6. In conclusion, both compounds exhibited marked hypotensive properties. PN 200-110 appeared to be more suitable for further development since its effects were found to be greater and much longer lasting than those of PY 108-068.

Animals↗

PubMed1988

[Influence of hypertension and age on the sympathetic and parasympathetic components of cardiac baroreflex in the conscious rat].

The influence of blood pressure (BP) level and age on the baroreflex sensitivity (BRS) and its autonomic nervous components was studied in genetically hypertensive (LH), normotensive (LN) and low blood pressure (LL) rats of the Lyon strains at 5, 9, 13 and 70 weeks of age. BRS was computed as the slope of the closest relationship, according to the cardiac response delay, between systolic blood pressure (SBP) and heart period changes induced by phenylephrine injections (3 micrograms/kg, i.v.) BRS and the relative importance of vagal and sympathetic components were determined in 4 conditions: 1) basal; 2) after beta-adrenergic blockade (propranolol, 2 mg/kg i.v.); 3) after vagal blockade (atropine, 2 mg/kg i.v.); 4) after vagal and beta-adrenergic blockade (atropine and propranolol, 2 mg/kg, i.v. each). At 5 weeks of age, BRS did not differ between the 3 strains (0.50 +/- 0.05, 0.69 +/- 0.10 and 0.62 +/- 0.09 ms/mmHg in LH, LN and LL rats respectively). In LN rats, BRS increased sharply between 5 and 9 weeks (1.25 +/- 0.12 ms/mmHg) and then remained stable until 70 weeks of age (1.19 +/- 0.14 ms/mmHg). Such an increase did not occur in LH rats and their BRS value was lower than that of LN and LL controls starting from 9 weeks of age. The vagal component of BRS was found to be more important than the sympathetic one in adult rats whatever the strain (80 p. 100 vs 20 p. 100).(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1986

Antihypertensive effects of S9490-3, a new converting enzyme inhibitor, in the conscious spontaneously hypertensive rat.

The acute and chronic cardiovascular effects of S9490-3, a new converting enzyme inhibitor, were studied by means of a computerized analysis of the intra-aortic blood pressure recorded for 48 consecutive hours, in the conscious, unrestrained adult spontaneously hypertensive rat (SHR). The software used allowed the simultaneous study of one control and one treated animal. A single intravenous dose of S9490-3 (2 mg/kg) induced a rapid fall in systolic and diastolic blood pressure, which remained significant for 11 h. This decrease was not associated with an elevation in heart rate. A chronic oral treatment with S9490-3 (1 mg/kg/24 h for 12 days) significantly lowered systolic and diastolic blood pressure and reduced the variability of systolic blood pressure. The heart rate was slightly increased at rest (day time) but significantly elevated in the freely exercising SHR (night time). However, it must be noted that this increase remained moderate. The baroreflex sensitivity of chronically treated animals was enhanced when measured after phenylephrine but not after nitroglycerine bolus. Chronically given S9490-3 significantly reduced the pressor effect of phenylephrine and decreased the left ventricle weight.

Administration, Oral↗

PubMed1986

Blood pressure and baroreflex sensitivity in conscious hypertensive rats of Lyon strain.

The evolution with age of blood pressure (BP), heart rate (HR), and baroreflex sensitivity was studied in hypertensive (LH), normotensive (LN), and low blood pressure (LL) male rats of the Lyon strains. Intra-arterial BP was continuously recorded for 48 h in freely moving animals. On-line computer analysis of the BP curve allowed calculation of systolic (SBP), mean (MAP), and diastolic (DBP) blood pressure, HR, and their variability. At 5 wk of age, LH rats exhibited a higher BP than LN and LL controls, which, at 21 wk of age, was associated with significant bradycardia and a greater variability in DBP and HR. LL rats had a MAP similar to LN, which confirms that both strains are, in terms of BP, valid controls for LH animals. The baroreflex sensitivity measured after phenylephrine injections increased with age more markedly in LN and LL than in LH rats, whereas in the latter, it was significantly lower at the age of 9 and 21 wk. When measured after nitroglycerin injections, the baroreflex sensitivity was higher and more stable than that observed after phenylephrine administration. In addition, the baroreflex sensitivity in the different strains was inversely related to the level and the variability of DBP but not of HR.

Aging↗

PubMed1985

Computer analysis of intraarterially recorded blood pressure in conscious unrestrained rats.

A precise knowledge of cardiovascular activity and its pharmacological modifications in the conscious unrestrained animal requires intraarterial blood pressure recording for long periods of time. For that purpose, a technique was developed involving chronic catheterization of the rat abdominal aorta and the use of a computer system to perform the digitization of the blood pressure signal and the on-line calculation of five cardiovascular parameters. By means of duplexing, two rats (one treated and one control) can be studied simultaneously. Off-line processing is devoted to the graphic treatment and statistical analysis of the data. The effects of a single intravenous administration of dihydralazine are presented in order to show the usefulness of the technique.

Animals↗

PubMed1985

Computer analysis of cardiovascular activity in conscious unrestrained hypertensive rats of the Lyon strain.

A new computerized technique was developed for the continuous analysis of intra arterially recorded blood pressure (BP) curve in freely moving rats during long periods of time. For each cardiac cycle 5 parameters were calculated on-line and stored. Off-line processing allowed graphical display and statistical analysis. This technique demonstrated that 21 week-old genetically hypertensive rats from the Lyon strain (LH) exhibited higher and more variable BP and dp/dt max. with a lower heart rate than normotensive (LN) and low blood pressure (LL) controls. LL rats differed from LN by a slightly higher systolic and a lower diastolic BP.

Animals↗

PubMed1985

Cardiovascular effects of S 9490-3, a new converting enzyme inhibitor: a computerized study in conscious spontaneously hypertensive rats.

The acute cardiovascular effects of S 9490-3, a new angiotensin converting enzyme (ACE) inhibitor, were studied by means of a computerized analysis of the intra-aortic blood pressure (BP), recorded continuously for 48 h in conscious, unrestrained, adult spontaneously hypertensive rats (SHR). The first 24-h recording period was used as a control. On the second day, the rats received a single intravenous (i.v.) injection of S 9490-3 (0.2 mg/kg) at 11 a.m. followed by another 2 mg/kg i.v. injection at 3 p.m. Cardiovascular activity was studied up to 8 a.m. the next day. No significant cardiovascular effects appeared after the 0.2 mg/kg dose, whereas the 2 mg/kg dose induced a rapid fall in systolic and diastolic BP, which remained significant for about 11 h. This BP decrease was not associated with any elevation in heart rate, but with a short lasting increase in dP/dt max. These results are in good agreement with those already obtained with S 9490-3 in various experimental conditions. They suggest that long-term recordings of intra-arterial BP in freely moving rats is of value in the study of drugs which act on the cardiovascular system.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1984

[Computerized analysis of cardiovascular activity in the conscious unrestrained rat. Application to the study of a new antihypertensive agent].

A more precise knowledge of cardiovascular activity in rats needs its direct recording for long periods of time, in conscious unrestrained animals. A system has been developed, which allows direct recording of blood pressure (BP) in freely moving rats, by means of a floating catheter chronically inserted in the abdominal aorta, connected to a rotating swivel, and then to a pressure transducer. A mini-computer performs on-line processing of BP curves, and stores the values of 5 cardiovascular parameters on hard disk: systolic, diastolic and mean arterial pressures, heart rate and dp/dt max. Off line processing allows graphic and statistical analysis of the data. Simultaneously recording from two rats is very useful in pharmacology because a treated animal and a control one are studied at the same time and in the same conditions. This methodology was used to evaluate the effects of a chronic treatment (2 mg/kg, ip, during 8 days) and of single injections (0.5 and 3 mg/kg, iv) of a new antihypertensive substance, CM 40441a, in 15 W old males SHR.

Adrenergic beta-Antagonists↗

PubMedDate not supplied

[Markers of cardiovascular remodeling in hypertension].

UNLABELLED: Our goal was to study the relative influence of systolic blood pressure (SBP) and plasmatic markers of sympathetic and renin-aldosterone systems (RAS) activities to left atrial diameter (LAD), left ventricular posterior wall thickness (LVPWT) and pulse wave velocity (PWV), which reflect cardiovascular remodeling in hypertension. METHODS: In 227 consecutive patients with hypertension (mean age +/- SD: 53.3 years +/- 13.4, 126 men), we measured: PWV, LAD, LVPWT, mean 24-hours SBP, plasma renin activity, and plasma aldosterone and catecholamine levels. Multiples linear regression analyses were performed to test statistical associations between hemodynamic and neurohumoral factors, and cardiovascular remodeling parameters, after adjustment for age, gender and body mass index. RESULTS: LVPWT was positively correlated to SBP as well as to plasma aldosterone and meta-noradrenaline (p < 0.001). LAD and PWV were related to SBP but not to any of the biological variables. Moreover, LAD correlated to PWV independently of SBP (p < 0.05), whereas after SBP inclusion in the model, there was not significant correlation between LAD and LVPWT nor between LVPWT and PWV. CONCLUSION: In hypertension, the development of cardiac hypertrophy depends on SBP and the sympathetic and renin-aldosterone systems activities. The RAS is not involved in the PWV nor LAD modifications. Strong association between LAD and PWV suggest that left atrial enlargement, that may be considered as a marker of diastolic function, may results more from arterial stiffness than from ventricular hypertrophy.

Adult↗

PubMedDate not supplied

[Risk profiles of hypertension in normotensive subjects].

The aim of this study was to evaluate the influence of 10 factors suspected to be involved in hypertension genesis (age, body mass index, alcohol consumption, sodium to potassium urinary excretion ratio, systolic BP and heart rate response to mental stress, baroreflex sensitivity (BRS), job demand, job latitude (Karasec's questionnaire), and personality (Bortner's score). A cohort of 213 normotensive healthy subjects was followed during five years. Using K-means clustering technique we have defined 7 homogeneous groups of subjects. Four groups with different combinations of these factors had a significantly higher 5-year systolic BP increase. The common characteristic of these groups was a low BRS. In conclusion, cluster analysis is well suited to analyse combined effect of factors on hypertension genesis. Only low BRS seems to be the common factor involved in hypertension development.

Adolescent↗

PubMedDate not supplied

[Expression of cytokines and their receptors in left ventricular hypertrophy in TGR(mRen2)27 rats].

Variations in the expression of cytokines from the interleukin-6 (IL-6) family: ciliary neurotrophic factor (CNTF), leukaemia inhibitory factor (LIF), and cardiotrophin 1 (CT-1) were studied during cardiac remodelling leading to left ventricular hypertrophy (LVH) in TGR(mRen2)27 rats at the age of 8 and 20 weeks. The cytokines mRNA levels within the free wall of the left ventricle were measured by semi-quantitative RT-PCR standardised with 18S. They were compared between heterozygous rats for the mRen2 transgene (TG+/-) and control rats (TG-/-). No significant difference was observed between results obtained at 8 and 20 weeks of age. At 20 weeks of age, TGR(mRen2)27 rats showed higher levels of mRNA LIF and IL-6 respectively by 52 and 55% compared to the control rats [LIF TG+/-: 3.17 +/- 0.21, TG-/-: 2.09 +/- 0.03; p < 0.001; n = 5; and IL-6 TG+/-: 1.53 +/- 0.13; TG-/-: 0.99 +/- 0.17; p < 0.05; n = 5]. By contrast, no variation of mRNAs levels of CT-1 and gp 130 genes was observed between control and transgenic rats. Concerning the cytokine receptors, the levels of mRNA for IL-6R did not vary while those of receptor subunits LIFR and CNTFR were decreased respectively by 48 and 42% in transgenic rats vs controls [LIFR TG+/-: 0.48 +/- 0.01; TG-/-: 0.92 +/- 0.08 p < 0.001; n = 5; and CNTFR TG+/-: 1.07 +/- 0.08; TG-/-: 1.85 +/- 0.18; p < 0.01; n = 5]. Therefore, these results show a specific pattern of activation of the cytokines pathway in the LVH of the TGR(mRen2)27 rat.

Animals↗

PubMedDate not supplied

[Is the white coat effect an alert reaction?].

Is the white coat effect an alert reaction? In this cross-sectional study we compared the white coat effect on systolic blood pressure with the systolic blood pressure reactivity obtained during a stress test. The influence of the sympathetic system (LF band of systolic BP) and the parasympathetic system (HF band of pulse rate) on white coat systolic blood pressure and stress test systolic blood pressure were analysed. We stratified 174 subjects into two groups, according to their blood pressure: hypertensives (HT, n=44, BP>140/90 mmHg) and normotensives (NT, n=130). The BP was recorded during an occupational health consultation, over 24 hours, and beat to beat during a stress test (Finapress). White coat systolic BP was calculated as the difference between the consultation BP and the average systolic BP over 24 hours. The white coat systolic BP was not related with an increase in pulse rate. In contrast, during the stress test the increases in systolic BP and pulse rate were correlated (r=0.44; p<0.001). The white coat systolic BP was lower than the stress test systolic BP in the NT (6.6 +/- 7.2 vs 23 +/- 12 mmHg; p<0.001) and in the HT (16 +/- 11 vs 29 +/- 17 mmHg; p<0.001). The HT had a lower parasympathetic index than the NT (0.45 +/- 0.43 vs 0.92 +/- 0.83 bpm2; p<0.001). In the HT the white coat systolic BP was positively correlated with the stress test systolic BP (r=0.47: p<0.01) and negatively with the parasympathetic activity index. In conclusion, for recently diagnosed and untreated HT an early alteration of the parasympathetic system reveals that the white coat effect is a low amplitude alert reaction.

Adult↗