Diurnal rhythms of blood pressure, heart rate, and locomotor activity in adult and old male Wistar rats

2000 ◽  
Vol 70 (3-4) ◽  
pp. 375-380 ◽  
Author(s):  
B Zhang
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Locomotor Activity ◽  
Wistar Rats ◽  
Diurnal Rhythms ◽  
Male Wistar Rats

Effects of photoperiod reduction on rat circadian rhythms of BP, heart rate, and locomotor activity

2000 ◽  
Vol 279 (1) ◽  
pp. R169-R178 ◽  
Author(s):  
Bei-Li Zhang ◽  
Erika Zannou ◽  
Frédéric Sannajust
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Locomotor Activity ◽  
Circadian Rhythms ◽  
Wistar Rats ◽  
Dark Period ◽  
Dark Phase ◽  
Mean Values ◽  
Shift Response ◽  
H 20

The effects of a photoperiod reduction in the entrainment of circadian rhythms of systolic blood pressure (SBP), diastolic blood pressure (DBP), heart rate (HR), and spontaneous locomotor activity (SLA) were determined in conscious Wistar rats by using radiotelemetry. Two groups of seven rats were maintained in a 12:12-h light-dark (12L/12D) photoperiod for 11 wk and then placed in a reduced photoperiod of 8:16-h light-dark (8L/16D) by advancing a 4-h darkness or by advancing and delaying a 2-h darkness for 6 wk. Finally, they were resynchronized to 12L/12D. Advancing a 4-h dark phase induced a 1-h advance of acrophase for SBP, DBP, and HR, but not for SLA. The percent rhythm, amplitude, and the 12-h mean values of all parameters were significantly decreased by the photoperiod reduction. When symmetrically advancing and delaying a 2-h dark phase, a 1 h 20 min delay of acrophases and a decrease in percent rhythms and amplitudes of SBP, DBP, HR, and SLA were observed. Only the 12-h mean values of HR and SLA were decreased. Our findings show that the cardiovascular parameters differ from SLA in phase-shift response to photoperiod reduction and that the adjustment of circadian rhythms to change from 12L/12D to 8L/16D photoperiod depends on the direction of the extension of the dark period.

scholarly journals To compare the blood pressure and heart rate during course of various types of anesthesia in wistar rat: A novel experiences

2018 ◽  
Vol 9 (6) ◽  
pp. 37-39
Author(s):  
Jagdish Narayan ◽  
Pradeep Kumar ◽  
Ankit Gupta ◽  
Sunita Tiwari
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Body Weight ◽  
Wistar Rats ◽  
Wistar Rat ◽  
Medical Sciences ◽  
The Awakening ◽  
Group I ◽  
Male Wistar Rats ◽  
Thiopental Sodium

Background: Rats are commonly used animals in development of newer drugs, rectification of toxicity and to record the various alterations in physiological parameters following pharmacological and non pharmacological interventions.Aim and Objectives: The purpose of this study was to identify the best physiological window during anesthesia. Therefore, we compared the effect of anesthesia using combination of ketamine and xylazine (KX) and thiopental sodium (intraperitoneally) on blood pressure and heart rate in adult male Wistar rats. Material and Methods: Twelve, male Wistar rats with a mean body weight of 260 ± 15 g were acquired. Thiopental sodium and cocktail of ketamine and xylazine (KX) were administered (ip) in group- I and group-II respectively. The systolic blood pressure and heart rate was recorded in both the groups till the awakening phase.Results: We found that there was a constant SBP and HR in Ketamine/Xylezine groups that are from 30 to 90 minutes after injection of anesthesia while this window was not observed in thiopental group.Conclusion: Our study concludes that the best time to observe the effect of newer drug during period between 30- 90 minutes after anesthesia.Asian Journal of Medical Sciences Vol.9(6) 2018 37-39

Attenuation of aortic baroreflex responses by microinjections of endomorphin-2 into the rostral ventrolateral medullary pressor area of the rat

2005 ◽  
Vol 289 (1) ◽  
pp. R59-R67 ◽  
Author(s):  
Ken Kasamatsu ◽  
Hreday N. Sapru
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Opioid Receptors ◽  
Wistar Rats ◽  
Inhibitory Effect ◽  
Blocking Effect ◽  
General Area ◽  
Baseline Blood Pressure ◽  
Male Wistar Rats ◽  
Μ Opioid Receptors

The presence of μ-opioid receptors and endomorphins has been demonstrated in the general area encompassing the rostral ventrolateral medullary pressor area (RVLM). This investigation was carried out to test the hypothesis that endomorphins in the RVLM may have a modulatory role in regulating cardiovascular function. Blood pressure and heart rate (HR) were recorded in urethane-anesthetized male Wistar rats. Unilateral microinjections of endomorphin-2 (0.0125–0.5 mmol/l) into the RVLM elicited decreases in mean arterial pressure (16–30 mmHg) and HR (12–36 beats/min), which lasted for 2–4 min. Bradycardia was not vagally mediated. The effects of endomorphin-2 were mediated via μ-opioid receptors because prior microinjections of naloxonazine (1 mmol/l) abolished these responses; the blocking effect of naloxonazine lasted for 15–20 min. Unilateral stimulations of aortic nerve for 30 s (at frequencies of 5, 10, and 25 pulses/s; each pulse 0.5 V and 1-ms duration) elicited depressor and bradycardic responses. These responses were significantly attenuated by microinjections of endomorphin-2 (0.2 and 0.4 mmol/l). The inhibitory effect of endomorphin-2 on baroreflex responses was prevented by prior microinjections of naloxonazine. Microinjections of naloxonazine alone did not affect either baseline blood pressure and HR or baroreflex responses. These results indicate that endomorphin-2 elicits depressor and bradycardic responses and inhibits baroreflex function when injected into the RVLM. These effects are consistent with the known hyperpolarizing effect of opioid peptides on RVLM neurons.

Chemoreceptor-sensitive neurons in commissural subnucleus of nucleus tractus solitarius of the rat

1995 ◽  
Vol 268 (4) ◽  
pp. R851-R858 ◽  
Author(s):  
V. C. Chitravanshi ◽  
H. N. Sapru
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Carotid Body ◽  
Phrenic Nerve ◽  
Wistar Rats ◽  
Nucleus Tractus Solitarius ◽  
Nerve Activity ◽  
Baroreceptor Stimulation ◽  
Male Wistar Rats ◽  
Arterial Pulses

Experiments were carried out in pentobarbital-anesthetized, vagotomized, paralyzed, and artificially ventilated male Wistar rats with a pneumothorax. Blood pressure, heart rate, and phrenic nerve activity were recorded. Extracellular neuronal recordings were made by glass micropipettes in a midline area in the commissural subnucleus of the nucleus tractus solitarius. At the end of the experiment, the recording sites were marked. Chemoreceptors were stimulated by tracheal administration of N2 or injection of CO2-saturated saline (50 microliters) near the carotid body. The baroreceptors were stimulated by an intravenous injection of phenylephrine (1-3 micrograms). Neurons that were excited by chemoreceptor stimulation but not baroreceptor stimulation were found in the commissural subnucleus of nucleus tractus solitarius and were designated as chemoreceptor-sensitive neurons. They exhibited a continuous discharge (9.9 +/- 1.3 spikes/s) that showed no apparent relation to either phrenic nerve bursts or arterial pulses. Such neurons were not found in the rostral portions of the nucleus tractus solitarius. These results confirm and extend our previous reports in which a discrete chemoreceptor projection site was identified in the commissural subnucleus of the rat.

The effect of neonatal treatment of rats with nerve growth factor on the blood pressure and structure of the mesenteric arteries

1992 ◽  
Vol 70 (8) ◽  
pp. 1154-1160 ◽  
Author(s):  
Robert M. K. W. Lee ◽  
Michael Coughlin ◽  
Jim Tsoporis ◽  
Chiu-Yin Kwan ◽  
Yong-Yuan Guan ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Nerve Growth Factor ◽  
Growth Factor ◽  
Wistar Rats ◽  
Mesenteric Arteries ◽  
Nerve Growth ◽  
Neonatal Treatment ◽  
Male Wistar Rats ◽  
And Control

Newborn male Wistar rats were treated with nerve growth factor daily by subcutaneous injection for 2 weeks, and control rats were treated with either cytochrome c or buffered saline. Average body weight of the treated animals was lower than that of the controls during the 2 weeks of treatment, but became similar to that of the controls thereafter. Tissue levels of norepinephrine were elevated in the brain, adrenal glands, mesenteric arteries, and vas deferens of the treated animals immediately after the treatment, but became similar in the three groups 2 weeks after the termination of the treatment. Blood pressure and heart rate were measured beginning at 4 weeks of age until 28 weeks, when the rats were sacrificed and the mesenteric arteries sampled for morphometric measurements of vessel wall dimensions. Pretreatment with nerve growth factor did not affect blood pressure, nor heart rate. Structural alteration of the three types of mesenteric arteries was also absent in the treated animals. We conclude that even though neonatal treatment of normal Wistar rats with nerve growth factor for 2 weeks induced an elevation of the norepinephrine levels in several tissues at the end of the treatment period, it was not sufficient to produce hypertension and structural alterations in the blood vessels.Key words: nerve growth factor, sympathetic nerve, hypertension, vascular changes, morphometry.

scholarly journals Hemodynamic and thermoregulatory effects of xylazine-ketamine mixture persist even after the anesthetic stage in rats

2012 ◽  
Vol 64 (4) ◽  
pp. 860-864 ◽  
Author(s):  
C. Picollo ◽  
A.J. Serra ◽  
R.F. Levy ◽  
E.L. Antonio ◽  
L. dos Santos ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Diastolic Blood Pressure ◽  
Rectal Temperature ◽  
Wistar Rats ◽  
Complete Recovery ◽  
Anesthetic Depth ◽  
Awake State ◽  
Male Wistar Rats ◽  
And Control

The xylazine-ketamine mixture (KX) is an anesthetic approach commonly administered to assess cardiovascular function in rodents. This study aimed to examine if the cardiovascular and thermoregulatory effects of KX could persist after the anesthetic state ceased in rats. Male Wistar rats were anesthetized with K (50mg/kg) X (10mg/kg) through the intra-peritoneal route. Hemodynamic and thermoregulatory repercussions were evaluated in animals in awake state, during an anesthetic depth and after complete recovery of anesthetized state. KX was efficient to significantly induce deep anesthesia in all rats after 10min. A complete recovery of anesthetized state was observed only after 210min. Compared with preanesthetic state and control animals that received no drug, KX induced a significant reduction of systolic and diastolic blood pressure at 10min. Hypotension was more prominent at 150min. The heart rate was also significantly reduced after 10 min of KX and the highest magnitude of bradycardia was observed at 30min. In addition, rectal temperature was markedly decreased at 30min of KX and the higher reduction occurred at 150min. The hemodynamic and thermoregulatory effects of KX were maintained even after complete anesthetic recovery.

scholarly journals Subtle Cardiovascular Dysfunction in the Unilateral 6-Hydroxydopamine-Lesioned Rat

2010 ◽  
Vol 2010 ◽  
pp. 1-10 ◽  
Author(s):  
K. Slack ◽  
R. Billing ◽  
S. Matthews ◽  
H. N. Allbutt ◽  
R. Einstein ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Locomotor Activity ◽  
Core Body Temperature ◽  
Diurnal Rhythms ◽  
Sensorimotor Function ◽  
Cardiovascular Autonomic Dysfunction ◽  
Sham Surgery ◽  
6 Hydroxydopamine ◽  
Core Body

The present study evaluated whether the unilateral 6-hydroxydopamine (6-OHDA) model of Parkinson's disease produces autonomic deficits. Autonomic parameters were assessed by implanting a small radiofrequency telemetry device which measured heart rate variability (HRV), diurnal rhythms of heart rate (HR), core body temperature (cBT) and locomotor activity (LA). Rats then received 6-OHDA lesion or sham surgery. 6-OHDA lesioned rats exhibited head and body axis biases, defective sensorimotor function (“disengage” test), and prominent apomorphine rotation (allP<.05versus controls). Diurnal rhythm of HR was lower for 6-OHDA lesioned rats (n=8) versus controls (n=6;P<.05). Whilst HR decreased similarly in both groups during the day, there was a greater decrease in HR for the 6-OHDA lesioned rats at night (by 38 b.p.m. relative to 17 b.p.m. for controls). LA and cBT did not differ between surgery groups. This study indicates the unilateral 6-OHDA model of PD shows subtle signs of cardiovascular autonomic dysfunction.

Radiotelemetric characterization of overweight-associated rises in blood pressure and heart rate

1999 ◽  
Vol 277 (4) ◽  
pp. H1540-H1545 ◽  
Author(s):  
Heinz Rupp ◽  
Bernhard Maisch
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Locomotor Activity ◽  
Caloric Intake ◽  
Cardiac Myosin ◽  
Myosin V ◽  
Pressure Transducers ◽  
Rate Maximum ◽  
Fat Diets

We addressed the hypothesis that hypercaloric diets induce hyperkinetic hypertension irrespective of day-night cycle and locomotor activity that is associated with altered cardiac myosin isozymes. Normotensive rats with implanted radiotelemetry pressure transducers were fed increasing amounts of coconut fat (8, 16, and 24%, each for 2 wk) corresponding to 20–47% of total calories from fat. Thereafter, increasing amounts of sucrose (16, 32, and 50%) and fructose (50%) were added to the 24% fat diet corresponding to 13–40% of total calories from sugar. In contrast to the fat diets, the 32% and 50% sucrose diets as well as the 50% fructose diets increased ( P < 0.05) blood pressure (systolic maximum +13 mmHg, diastolic maximum +4 mmHg, mean maximum +7 mmHg) and heart rate (maximum +50 beats/min) irrespective of the day-night cycle and the unaltered locomotor activity. Furthermore, body weight increased ( P < 0.05) during the 32% and 50% sucrose feedings. The increased blood pressure and heart rate normalized after rats were fed a regular chow. We concluded that an excessive caloric intake results in hyperkinetic hypertension that increases the myosin V1proportion.

Dietary linoleic acid and salt-induced hypertension

1981 ◽  
Vol 59 (8) ◽  
pp. 872-875 ◽  
Author(s):  
Murray C. Macdonald ◽  
Robert L. Kline ◽  
Gordon J. Mogenson
Keyword(s):  
Blood Pressure ◽  
Linoleic Acid ◽  
Systolic Blood Pressure ◽  
Wistar Rats ◽  
Sodium Content ◽  
Significant Elevation ◽  
Dietary Linoleic Acid ◽  
Low Level ◽  
Induced Hypertension ◽  
Male Wistar Rats

Male Wistar rats chronically fed a low level (0.41%) of linoleic acid (LA) in the diet as supplied by 5% olive oil developed a significant elevation of systolic blood pressure as compared with rats fed either a medium (4.2%) or high (9.4%) level of dietary LA. Chronic excess intake of NaCl (3.75% in the diet) was associated with a significant elevation of blood pressure on all three diets but a low level of LA in the diet exaggerated the salt-induced hypertension. The results suggest that inadequate dietary LA may result in an increase in systolic blood pressure regardless of the sodium content of the diet.

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