Effects of TJN-220 on Blood Pressure, Heart Rate and Activity in Freely Moving Spontaneously Hypertensive Rats as Determined by a Radio-telemetry System

The aim of this work was to investigate the effect of 10 weeks of lisinopril treatment to spontaneously hypertensive rats (SHRs) on day/night variations of blood pressure, heart rate and autonomic cardio-regulation parameters. Male SHR with surgically implanted radio-telemetry implant that provided direct measurements of arterial pressure and electrocardiogram wave were used. Animals were allocated to two groups (n=5 each). The first group was treated with lisinopril (20 mg/kg by gavage) daily for 10 weeks (treated group); whereas the second was gavaged daily with tap water (untreated group). Arterial blood pressure, ECG and other telemetry parameters were recorded at the start and at the end of 10-week treatment. Collected data were analyzed using specialized software and were statistically tested. In addition to the expected lowering of blood pressure, spectral analysis of R-R intervals revealed that lisinopril treatment for 10 weeks significantly caused 2-3 fold increase in heart rate variability (HRV) during both active and inactive periods. However, R-R interval durations demonstrated variable distribution patterns during those periods. The cause of observed distribution pattern of R-R intervals during active and inactive periods may be of significance to better understand HRV changes and warrants further investigations.

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Circadian rhythms of blood pressure, heart rate, and locomotor activity in spontaneously hypertensive rats as measured with radio-telemetry

Physiology & Behavior ◽

10.1016/0031-9384(94)90060-4 ◽

1994 ◽

Vol 55 (4) ◽

pp. 783-787 ◽

Cited By ~ 80

Author(s):

Maarten Van Den Buuse

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Locomotor Activity ◽

Circadian Rhythms ◽

Spontaneously Hypertensive Rats ◽

Radio Telemetry ◽

Hypertensive Rats ◽

Spontaneously Hypertensive

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Effects of Melatonin on Blood Pressure, Heart Rate and Activity in Conscious, Freely Moving Stroke-prone Spontaneously Hypertensive Rats as determined by a Radiotelemetry System

Japanese Heart Journal ◽

10.1536/ihj.34.491 ◽

1993 ◽

Vol 34 (4) ◽

pp. 491-491

Author(s):

Takashi Yamasaki ◽

Takeshi Negishi ◽

Kazuko Fujimoto ◽

Takeshi Suzuki ◽

Koichiro Kawashima

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Spontaneously Hypertensive Rats ◽

Hypertensive Rats ◽

Spontaneously Hypertensive ◽

Freely Moving

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Regression of myocardial hypertrophy and influence of adrenergic system

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1983.244.1.h97 ◽

1983 ◽

Vol 244 (1) ◽

pp. H97-H101 ◽

Cited By ~ 4

Author(s):

S. Sen ◽

R. C. Tarazi

Keyword(s):

Blood Pressure ◽

Heart Rate ◽

Regression Analysis ◽

Arterial Pressure ◽

Spontaneously Hypertensive Rats ◽

Myocardial Hypertrophy ◽

Cardiac Response ◽

Adrenergic System ◽

Hypertensive Rats ◽

Spontaneously Hypertensive

Studies of regression of myocardial hypertrophy in spontaneously hypertensive rats (SHR) suggest that the adrenergic system may play an important role in the reversal of hypertrophy. The effect of propranolol on reversal of hypertrophy, however, is still controversial. This study describes the effect of propranolol, given alone or in combination with hydralazine in different ratios for 4 wk, on blood pressure (BP), ventricular weight, and myocardial catecholamine (MC) concentrations. The data show that a certain ratio of propranolol to hydralazine (750:30) leads to moderate BP control (196-156 mmHg) without increased MC (634 vs. 552 ng/g) and moderately reduced hypertrophy. Reduction of BP alone with increased MC (hydralazine alone) or reduction of MC without BP control (propranolol alone) failed to reduce hypertrophy. A significant correlation between both ventricular weight and heart rate with MC (r = 0.6) was obtained by multiple regression analysis. This study suggests that adrenergic factors seem to play an important role in modulating structural cardiac response to variations in arterial pressure.

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