Decrease In Systolic Arterial Blood Pressure Research Articles

The effect of hydroalcoholic extract of Achillea eriophora DC. on blood pressure of anaesthetized male rat.

Achillea eriophora (Asteraceae) is a medicinal plant commonly used in Iran. This study was performed to determine the cardiovascular effects of hydroethanolic extract of A. eriophora (HEAE) and the underlying mechanisms in anaesthetized rats. The acute effects of intravenous (i.v.) administration of different doses of HEAE (40, 50, 60, 80 mg/kg), and its probable interaction with cholinergic and nitrergic systems were investigated in the presence of ACh and NOS blocker (L-NAME) as well as ethanol (HEAE solvent in sham group). Intravenous administration of different doses of HEAE induced hypotension. HEAE (60 mg/kg) significantly reduced mean arterial blood pressure (MAP), systolic arterial blood pressure (SBP) and diastolic arterial blood pressure (DBP) compared to control rats that treated with ethanol only, but no change in heart rate (HR) was seen in both groups. The results showed significant decrease in MAP, SBP, DBP and increase of HR in the presence of HEAE plus ACh (10 µg/kg) compared to when ACh was injected alone. Finally i.v. administration of HEAE, significantly reduced MAP and DBP in L-NAME (5 mg/kg) treated animals, while bradycardic responses to L-NAME were not significantly changed by HEAE. It can be concluded that Achillea eriophora induced hypotensive effect via lowering total peripheral resistance and cardiac output that may be synergist with cholinergic and independent of nitrergic system.

Systolic arterial blood pressure in small-breed dogs with degenerative mitral valve disease: A prospective study of 103 cases (2007–2012)

The objective of this prospective observational study was to assess systolic arterial blood pressure (SABP) in small-breed dogs with degenerative mitral valve disease (MVD) from different International Small Animal Cardiac Health Council (ISACHC) heart failure classes. For this purpose, 103 client-owned dogs weighing <20kg (mean±standard deviation, 8.5±3.0kg; aged 9.8±2.9years) and presenting with MVD diagnosed by echo-Doppler examination were enrolled. Nineteen healthy dogs (9.9±2.3years; 8.7±4.2kg) were concurrently recruited as controls. SABP was measured in unsedated dogs using the Doppler method according to the recommendations in the American College of Veterinary Medicine consensus statement.SABP was significantly increased in dogs in ISACHC class 1 (n=53; median, interquartile range 140mmHg, 130–150mmHg) and class 2 (n=21; 140mmHg, 130–150mmHg), compared to the control group (n=19; 130mmHg, 120–140mmHg; P<0.01 and P<0.05, respectively), but remained within the reference interval (⩽160mmHg). Conversely, dogs in ISACHC class 3 showed a significantly lower SABP (n=29, 120mmHg, 110–130mmHg) than those from all other ISACHC classes (P<0.001) and the controls (P<0.05). Additionally, SABP<120mmHg was recorded in 13/103 dogs (13%). The 13 dogs were all ISACHC class 3 (3a or 3b) and were under medical treatment for heart failure. In conclusion, MVD was often associated with SABP values that were within the reference interval, but at its upper end. However, a significant decrease in SABP was observed in dogs with ISACHC heart failure class 3. Whether such low SABP values resulted from an MVD-related decrease in cardiac output, an afterload reduction owing to cardiac treatment, or both, remains to be determined.

Knocking down the diencephalic thyrotropin-releasing hormone precursor gene normalizes obesity-induced hypertension in the rat

We recently showed that diencephalic TRH may mediate the central leptin-induced pressor effect. Here, to study the role of TRH in obesity-induced hypertension (OIH), we used a model of OIH produced by a high-fat diet (HFD, 45 days) in male Wistar rats. After 4 wk, body weight and systolic arterial blood pressure (SABP) increased in HFD animals. Plasma leptin was correlated with peritoneal adipose tissue. Then, we treated OIH animals with an antisense oligodeoxynucleotide and small interfering (si)RNA against the prepro-TRH. Antisense significantly decreased diencephalic TRH content and SABP at 24 and 48 h posttreatment. Similar effects were observed with siRNA against prepro-TRH but for up to 4 wk. Conversely, vehicle, an inverted antisense sequence and siRNA against green fluorescence protein, produced no changes. SABP decrease seems to be owing to an inhibition of the obesity-enhanced sympathetic outflow but not to an alteration in thyroid status. Using a simple OIH model we demonstrated, for the first time, that central TRH participates in the hypertension induced by body weight gain probably through its well-known action on sympathetic activity. Thus the TRH-leptin interaction may contribute to the strong association between hypertension and obesity.

Effects of Blood Donation on Arterial Blood Pressure in Retired Racing Greyhounds

The purpose of this study was to evaluate changes in systolic arterial blood pressure (SABP) immediately after collection of blood for transfusion in retired racing Greyhounds. We prospectively evaluated 19 blood donor Greyhounds before and after the collection of a unit (450 mL) of blood. The SABP was measured with Doppler in the right forearm after the dogs had been in the blood collection room for a few minutes (PRE-FLOOR) and again 5–10 minutes after the dogs were placed on the table where they would be bled (PRE-TABLE). A total of 3–5 minutes after completing the blood collection, the SABP was measured again while the dogs were still in lateral recumbency on the table (POST-TABLE) and once more 60–90 minutes later, when the dogs were on the floor after completing the donation (POST-FLOOR). All dogs were monitored for clinical signs of hypotension, including depression, weakness, collapse, and pallor, for a minimum of 2 hours after donation. There was a significant difference in SABP for the group between PRE-FLOOR and POST-TABLE (P= .02) and between PRE-TABLE and POST-TABLE determinations (P= .01). There were no significant differences for any of the other time points; there were no adverse events. Therefore, we conclude that the collection of 450 mL of blood from normal Greyhounds results in a short-lived yet significant decrease in SABP but the likelihood of adverse events is negligible.

Cardiovascular parameters in anaesthetized guinea pigs: A safety pharmacology screening model

Introduction Assessment of cardiovascular functions in vivo is part of the core battery of guideline ICH S7A and is thereby required by regulatory authorities. The haemodynamic effects of repeated intravenous administrations of reference compounds were analyzed in order to validate the guinea pig model for safety pharmacology studies under GLP conditions. Methods Male guinea pigs ( n = 54, weighing 565–762 g) were anaesthetized using 1.5 g/kg, i.p., urethane. Systolic arterial blood pressure (SAP), diastolic arterial blood pressure (DAP), heart rate (HR), left ventricular pressure (LVP), cardiac contractility (d p/d t max), and ECG (RR, QT, and QTc intervals) were recorded continuously. Animals received vehicle i.v. followed by cumulative doses of reference compounds. Results Vehicle did not produce any relevant changes, either in cardiovascular or ECG parameters. Isoproterenol caused a rapid and significant increase in HR, LVP, and d p/d t max, in contrast to a dose-dependent decrease in SAP and DAP. Epinephrine led to a potent increase in all cardiovascular parameters. Nifedipine produced a slight decrease in HR and LVP, and a potent decrease in blood pressure and d p/d t max. Verapamil caused a dose-dependent decrease in all cardiovascular parameters. Ouabain resulted in a significant increase in SAP, DAP, LVP, and d p/d t max; ECG showed an atrioventricular block and arrhythmia. Terfenadine, cisapride, and sotalol prolonged QT and QTc intervals, whereas vehicle and the other tested compounds did not produce any prolongation of the QTc interval. Discussion Our results on HR, blood pressure, and ECG obtained after i.v. administration of reference compounds show the usefulness of the guinea pig in assessing cardiovascular safety. The anaesthetized guinea pig allows the measurement of cardiac contractility and the use of doses higher than in conscious animals. Using this animal model, several cardiovascular parameters can be recorded simultaneously at a modest cost in terms of test compound and the number of animals required.

Effects of Blood Donation on Arterial Blood Pressure in Retired Racing Greyhounds

The purpose of this study was to evaluate changes in systolic arterial blood pressure (SABP) immediately after collection of blood for transfusion in retired racing Greyhounds. We prospectively evaluated 19 blood donor Greyhounds before and after the collection of a unit (450 mL) of blood. The SABP was measured with Doppler in the right forearm after the dogs had been in the blood collection room for a few minutes (PRE-FLOOR) and again 5-10 minutes after the dogs were placed on the table where they would be bled (PRE-TABLE). A total of 3-5 minutes after completing the blood collection, the SABP was measured again while the dogs were still in lateral recumbency on the table (POST-TABLE) and once more 60-90 minutes later, when the dogs were on the floor after completing the donation (POST-FLOOR). All dogs were monitored for clinical signs of hypotension, including depression, weakness, collapse, and pallor, for a minimum of 2 hours after donation. There was a significant difference in SABP for the group between PRE-FLOOR and POST-TABLE (P = .02) and between PRE-TABLE and POST-TABLE determinations (P = .01). There were no significant differences for any of the other time points; there were no adverse events. Therefore, we conclude that the collection of 450 mL of blood from normal Greyhounds results in a short-lived yet significant decrease in SABP, but the likelihood of adverse events is negligible.