The Effect of Intravenous Infusions of Angiotensin and Noradrenaline on Systolic Blood Pressure and Critical Opening Pressure of Tail Vessels in Conscious Rats

1974 ◽  
Vol 52 (4) ◽  
pp. 883-886 ◽  
Author(s):  
A. C. Darke
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Spectroscopic Technique ◽  
Opening Pressure ◽  
Conscious Rats ◽  
Critical Opening ◽  
Intravenous Infusions ◽  
Direct Recording ◽  
Indirect Technique ◽  
Human Finger

A spectroscopic technique for the measurement of systolic blood pressure and critical opening pressure of tail vessels in conscious rats is described. The values for systolic blood pressure obtained by this indirect technique were compared with those obtained by direct recording from a cannulated carotid artery. The correlation between the two sets of measurements was highly significant and the regression coefficient was very close to unity. In a separate series of experiments the effects of intravenous infusions of angiotensin or noradrenaline on the critical opening pressure of tail vessels were investigated in conscious ganglion-blocked rats. Both drugs produced dose-dependent increases in critical opening pressure and systolic blood pressure. This contrasts with the situation in the human finger where angiotensin has been shown to produce a decrease in critical opening pressure, indicating relaxation of a least some of the vessels in the finger, while at the same time producing an overall increase in digital vascular resistance.

The Influence of Lysine-8-vasopressin, Oxytocin, and Adrenaline on Vascular Smooth Muscle in the Human Finger

1973 ◽  
Vol 51 (4) ◽  
pp. 284-290 ◽  
Author(s):  
Peter Gaskell
Keyword(s):  
Blood Pressure ◽  
Smooth Muscle ◽  
Vascular Resistance ◽  
Young Women ◽  
Systemic Blood Pressure ◽  
Apparent Effect ◽  
Opening Pressure ◽  
Systemic Blood ◽  
Critical Opening ◽  
Human Finger

Lysine-8-vasopressin, oxytocin, or adrenaline was administered by intravenous infusion to young women, and their effect on the critical opening pressure (COP) of digital vessels, vascular resistance in the finger, and systemic blood pressure was measured. All doses of lysine-8-vasopressin between 0.001 and 0.08 U/min increased the COP of digital vessels but only the largest dose raised blood pressure slightly. A dose of 0.04 U/min had little if any effect on overall vascular resistance in the finger. Nevertheless the smallest dose given (0.001 U/min), which is within the physiological range of secretion rate by the pituitary gland, increased the COP of digital vessels substantially. Oxytocin at doses of 5–160 mU/min had no apparent effect on COP or vascular resistance of digital vessels or on blood pressure. Adrenaline at 4 μg/min increased the COP of digital vessels substantially. The latter observation is consistent with the absence of β receptors in vessels of the skin of the fingers.

THE MEASUREMENT OF BLOOD PRESSURE, THE CRITICAL OPENING PRESSURE, AND THE CRITICAL CLOSING PRESSURE OF DIGITAL VESSELS UNDER VARIOUS CIRCUMSTANCES

1965 ◽  
Vol 43 (6) ◽  
pp. 979-993 ◽  
Author(s):  
Peter Gaskell
Keyword(s):  
Blood Pressure ◽  
Nerve Block ◽  
Spectroscopic Method ◽  
Spectroscopic Technique ◽  
Opening Pressure ◽  
Small Vessels ◽  
Critical Opening ◽  
Critical Closing Pressure ◽  
Digital Nerve Block ◽  
Closing Pressure

A spectroscopic technique for the estimation of the critical opening pressure (COP) or critical closing pressure (CCP) of small vessels in the finger is described. The spectroscopic method of estimation of the systolic blood pressure, which is part of the technique and which involves the detection of reappearance of oxyhemoglobin absorption bands in the spectrum of reflected light from the skin distal to a blood pressure cuff that is slowly deflated, was compared to the auscultatory technique in 38 subjects on 53 occasions and gave the same results. The COP of small vessels in the finger estimated by the spectroscopic technique was decreased by body heating and by digital nerve block as had been previously shown by the microscopical method. The COP of vessels in the finger after digital nerve block in 43 normotensive young women between the ages of 18 and 22 years ranged from 2 to 19 mm Hg with a mean of 9.5 ± 4.6 (S.D.) mm Hg. When the COP was estimated in many of the same subjects after preparation as for measurement of the basal metabolic rate, in most cases it fell within the range of values obtained after nerve block. The COP in 26 subjects ranged from 1 to 22 mm Hg with a mean of 10.9 ± 5.0 (S.D.). The values for CCP estimated by the spectroscopic method in 81 individuals were not significantly different from those for COP estimated on the same occasion.

Critical opening pressure and reactivity of tail vessels in conscious hypertensive rats

1976 ◽  
Vol 54 (3) ◽  
pp. 314-321
Author(s):  
A. C. Darke ◽  
P. G. Nair ◽  
P. Gaskell
Keyword(s):  
Blood Pressure ◽  
Renovascular Hypertension ◽  
Vascular Reactivity ◽  
Experimental Hypertension ◽  
Hypertensive Rats ◽  
Opening Pressure ◽  
Critical Opening ◽  
Resistance Vessels ◽  
Before And After ◽  
Desoxycorticosterone Acetate

The possible role of increased vascular reactivity in the mechanism of experimental hypertension was studied by measurements of the critical opening pressure (COP) of tail vessels in conscious rats. In hypertension induced by administration of desoxycorticosterone acetate (DOCA) and replacement of the drinking water by 1% NaCl solution (DOCA–NaCl hypertension), and in one-kidney Goldblatt renovascular hypertension, the raised level of blood pressure was associated with an increased COP of the tail vessels when measured both before and after ganglionic blockade. In rats treated with either DOCA alone or 1% NaCl alone there was no significant increase in systolic blood pressure (SBP) or COP relative to the corresponding controls. In all four experimental series intravenous infusion of angiotensin or norepinephrine in conscious ganglion-blocked rats produced dose-dependent increases in SBP and COP. In DOCA–NaCl hypertensive rats but not in renovascular hypertensives, nor in rats treated with DOCA alone or 1% NaCl alone, the increase in COP for a given increment in dose of angiotensin or norepinephrine was significantly greater than in the control rats. It is concluded that in DOCA–NaCl hypertension there is a true increase in the reactivity of the smooth muscle of the resistance vessels to angiotensin and norepinephrine. In renovascular hypertension this is not the case and other factors must therefore be involved in causing the increased blood pressure and COP.

A Simple Versatile Method for Measuring Tail Cuff Systolic Blood Pressure in Conscious Rats

1997 ◽  
Vol 93 (3) ◽  
pp. 191-194 ◽  
Author(s):  
Robert E. Widdop ◽  
Xiao C. Li
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Electric Pulse ◽  
Current Method ◽  
Simple Method ◽  
Conscious Rats ◽  
Standard Data ◽  
Wistar Kyoto ◽  
Tail Cuff ◽  
Piezo Electric

1. The non-invasive measurement of tail cuff systolic blood pressure in conscious rats is routinely used in long-term cardiovascular studies. There are a number of commercially available tail cuff systems, however, these apparatus are generally expensive and are dedicated for single-task operations. In the present study, a simple method for measuring systolic blood pressure, which requires only minor modifications to the existing hardware found in most cardiovascular laboratories, is described. 2. Systolic blood pressure measurements were made in the conventional manner by determining the systolic blood pressure which coincided with the restoration of the caudal artery pulse. This was achieved by using an inexpensive piezo-electric pulse transducer to detect the pulse, and this was coupled to a standard data-aquisition system (MacLab®, ADInstruments) normally set up to record blood pressure. This method was compared with another established tail cuff method, as well as with direct intra-arterial recordings. 3. It was found that the results obtained using both tail cuff systems were in good agreement when systolic blood pressure was measured in Wistar—Kyoto rats and spontaneously hypertensive rats. In addition, systolic blood pressure was measured over 4 weeks in 2K1C rats and sham-operated rats, with both tail cuff methods producing similar results, which were not significantly different from direct intra-arterial recordings in the same animals. 4. Thus, in the present study, with only minor modifications, the same equipment was used for both direct and indirect determinations of systolic blood pressure. This situation differs from other conventional tail cuff systems since these items are designed for a single purpose. Therefore, the current method using piezo-electric sensor/MacLab®-technology should be viewed as a relatively simple, flexible and cheap alternative method to measure tail cuff systolic blood pressure in conscious rats.

scholarly journals Frequency components of systolic blood pressure variability reflect vasomotor and cardiac sympathetic functions in conscious rats

2011 ◽  
Vol 61 (5) ◽  
pp. 373-383 ◽  
Author(s):  
Takahiko Yoshimoto ◽  
Kunihiro Eguchi ◽  
Hiroki Sakurai ◽  
Yusuke Ohmichi ◽  
Tatsuyuki Hashimoto ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Systolic Blood Pressure ◽  
Blood Pressure Variability ◽  
Conscious Rats ◽  
Frequency Components ◽  
Systolic Blood Pressure Variability

Paradoxical Hypotension during Dobutamine Infusion for Myocardial Perfusion Scintigraphy

1998 ◽  
Vol 37 (08) ◽  
pp. 268-271
Author(s):  
B. Caner ◽  
E. Atalar ◽  
A. Karanfil ◽  
L. Tokgözoğlu ◽  
E. L. Ergün
Keyword(s):  
Blood Pressure ◽  
Myocardial Perfusion ◽  
Systolic Blood Pressure ◽  
Myocardial Perfusion Scintigraphy ◽  
Stress Test ◽  
Dobutamine Infusion ◽  
Perfusion Scintigraphy ◽  
Tilt Table ◽  
Study Results ◽  
Group A

Summary Aim: Dobutamine as a predominant beta-1 agonist increases heart rate and myocardial contractility and at sufficient high doses, it also increases systolic blood pressure. This study was undertaken to describe instances of paradoxical hypotension during dobutamine infusion for TI-201 myocardial perfusion SPECT study and the relationship between scintigraphic findings and hypotension occurred during dobutamine infusion. Methods: In 201 consecutive patients unable to perform adequate exercise, dobutamine TI-201 myocardial SPECT was performed. Dobutamine was infused starting from 10 μg/kg/min increasing to 40 μg/kg/min. Paradoxical hypotension was defined as a decrease in systolic blood pressure ≥ 20 mmHg compared with baseline study. Results: Paradoxical hypotension was observed in 40 patients (Group A) out of 201 (19.9%) while no significant change in systolic blood pressure was detected in the remaining 161 patients (Group B). Mean maximum fall in systolic blood pressure was 39 ± 18 mmHg (range: 20-90). In 33 of 40 patients (83%) with paradoxical hypotension, scintigraphy was normal compared to 131 (81%) of the remaining 161 patients. In patients of Group A, angiography, echocardiography and tilt table tests were performed in 13, 11 and 6 patients respectively. Nine of 13 angiographic evaluations (69%), 10 of 11 echocardiographic evaluations (91%), all of the tilt table tests were normal. Additionally, all of the patients of Group A were clinically followed up at least 6 months after the myocardial perfusion scintigraphy. None of the patients had a cardiac event except one patient during the follow-up period. Conclusion: Paradoxical hypotension during dobutamine infusion for myocardial scintigraphy is not an uncommon finding and up to 19.9% patients may develop such hypotension. To maximize test safety, precautions should be taken during dobutamine myocardial stress test, since remarkable decrease in systolic blood pressure may occur. Unlike hypotension occurring with exercise test, hypotension response to dobutamine is not always a marker for coronary artery disease.

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