Continuous blood pressure measurement in rats with aortic baroreceptor deafferentation

Fink, Gershon; Bryan, William Jennings; Mann, Mark; Osborn, Jeff; Werber, Andrew H.

doi:10.1152/ajpheart.1981.241.2.h268

Cited by 13 publications

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“…Comparable results were obtained from 1-hour and 24-hour recordings regardless of whether the mean or median value of each MAP frequency distribution was used (see Table 1). Thus, our results agree with those of Fink et al , 31 who found that brief daily recordings of intra-arterial pressure produced an average MAP that was the same as that calculated from continuous 24-hour recordings. However, their measurement procedure precluded assessment of the variability of the MAP during short-term recording sessions.…”

Section: Discussionsupporting

confidence: 93%

“…However, we noted that depressor responses were frequently associated with changes in body position or locomotion in SAD rats, an observation made in several other studies. 31 ' 4041 In contrast, the direction of change in the MAP of NTS lesion rats was not necessarily related to such behavior. Sinoaortic-denervated rats have been shown to exhibit augmented vasodepressor responses to centrally applied catecholamines.…”

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confidence: 95%

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Comparison of 1-hour and 24-hour blood pressure recordings in central or peripheral baroreceptor-denervated rats.

Buchholz¹,

Hubbard²,

Nathan³

1986

Hypertension

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SUMMARY We compared the mean arterial pressure and heart rate activity of conscious, unrestrained rats during 1-hour and 24-hour continuous recording sessions, 3 to 4 weeks after either sinoaortic denervation, placement of electrolytic lesions in the nucleus tractus solitarii, or sham operations. Sinoaortic denervation and nucleus tractus solitarii lesions both eliminated the reflex bradycardia to a phenylephrine-induced pressor response. No difference was found in the average level and lability of the mean arterial pressure between 1-hour and 24-hour recordings for any group. No elevation in the average mean arterial pressure of rats with nucleus tractus solitarii lesions was observed, although a mild hypertension was noted in half the sinoaortic-denervated rats, while the other half were normotensive. Group differences were not found for heart rate or heart rate variability; however, 24-hour recordings yielded significantly higher values than 1-hour recordings for all groups. Both medullary lesions and sinoaortic denervation significantly increased the lability of the mean arterial pressure, but the magnitude of the increase was significantly greater in the rats with lesions. The lability of the mean arterial pressure in sinoaortic-denervated rats depended largely on movement-related depressor responses that produced a negative skew in the frequency distribution of their mean arterial pressure. Rats with nucleus tractus solitarii lesions exhibited both pressor and depressor responses that resulted in pressure distributions that had a slight positive skew similar to that displayed by control rats. It is concluded that short-term continuous recordings of mean arterial pressure and heart rate accurately estimate the altered cardiovascular activity of baroreceptordenervated rats. T HE cardiovascular response to sinoaortic desurement, the duration of measurement, and the envinervation (SAD) has been studied in rats, ronment in which the arterial pressure was recordcats, rabbits, and dogs.

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Section: Discussionsupporting

confidence: 93%

mentioning

confidence: 95%

Comparison of 1-hour and 24-hour blood pressure recordings in central or peripheral baroreceptor-denervated rats.

Buchholz¹,

Hubbard²,

Nathan³

1986

Hypertension

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“…The lowest stable MAP recorded continuously for Ն10 minutes was taken as the value for the recording session. 13 …”

Section: Hemodynamic Measurementsmentioning

confidence: 99%

Renin Activity and Blood Pressure in Response to Chronic Episodic Hypoxia

1999

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Abstract-Previous studies in several strains of rats have demonstrated that 35 days of recurrent episodic hypoxia (EH) (7 hours per day), with a fractional concentration of inspired oxygen that produces desaturation equivalent to the recurrent hypoxemia of sleep apnea, results in an 8 to 13 mm Hg persistent increase in diurnal systemic blood pressure (BP). Carotid chemoreceptors and the sympathetic nervous system have been shown to be necessary for development of this BP increase. Both renal artery denervation and adrenal demedullation block the BP response to chronic EH. The present study was undertaken to define further the role of the kidneys and the renin-angiotensin system in this BP increase. Separate groups of male Sprague-Dawley rats had either (1) bilateral renal artery denervation with EH, (2) sham surgery with EH, (3) sham surgery with sham EH (compressed air), (4) EH with losartan, (5) unhandled with losartan, or (6) unhandled. The experimental period lasted 35 days. Both renal-artery denervated and losartan-treated animals showed no BP change or a lowering of BP in response to EH, whereas the sham-operated EH animals showed a progressive, sustained increase in resting room air BP. BP remained at basal levels or fell in unhandled and unhandled losartan-treated animals. Plasma renin activity was elevated 4-fold versus basal levels in EH animals with renal nerves intact but remained at baseline levels in denervated animals. At the end of the experiment, renal tissue catecholamines confirmed renal denervation in those animals. In conclusion, EH causes a progressive increase in BP, mediated in part through renal sympathetic nerve activity that acts to increase renin-angiotensin system activity through angiotensin II type 1 receptors. (Hypertension. 1999;34:309-314.)Key Words: hypoxia Ⅲ blood pressure Ⅲ denervation, renal Ⅲ sympathetic nervous system Ⅲ sleep apnea syndromes Ⅲ hypertension, systemic Ⅲ renin-angiotensin system R ecent publications have implicated increased sympathetic nervous system activity, driven by chemoreceptor response to progressive hypoxemia, as a contributing cause of acute elevation of blood pressure (BP) in patients with obstructive sleep apnea. 1-3 The mechanism for sustained diurnal rise in BP after many years of repetitive apnea remains a mystery, but chronic stimuli, including recurrent episodic hypoxia (EH), repeated arousals, or repetitive Mueller maneuvers, may contribute to it.We have developed a rat preparation that mimics the hypoxic changes seen in sleep apnea patients. With the use of individual cylindrical cages and a method for rapid exchange of inspired concentration of oxygen (FiO 2 ) to as low as 2% to 3%, arterial oxyhemoglobin saturation falls acutely to levels of Ϸ70% to 75%. Such EH, when administered repetitively (every 30 seconds for 7 hours per day for 35 days), increases resting, diurnal mean arterial pressure (MAP) by 8 to 13 mm Hg. 4 Chemoreceptor denervated 5 and chemical sympathectomy rats (neurotoxin 6-OH dopamine) 6 show no increase in MAP following...

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“…The remaining 50% could be considered to have a partial SAD, with their TGSI ranging from 8.09 to 8.24. On the other hand, several early studies (32)(33)(34)(35) focused on the cardiovascular and neural effects of AD (a form of partial barodenervation) in rats. However, the lack of any individual test for the extent of barodenervation makes it difficult to derive valid conclusions from these studies.…”

Section: Discussionmentioning

confidence: 99%

An improved strategy for evaluating the extent of chronic arterial baroreceptor denervation in conscious rats

Rodrı́guez-Martı́nez

Torres-Rodríguez

Brito-Orta

et al. 2010

Braz J Med Biol Res

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Continuous blood pressure measurement in rats with aortic baroreceptor deafferentation

Cited by 13 publications

References 0 publications

Comparison of 1-hour and 24-hour blood pressure recordings in central or peripheral baroreceptor-denervated rats.

Comparison of 1-hour and 24-hour blood pressure recordings in central or peripheral baroreceptor-denervated rats.

Renin Activity and Blood Pressure in Response to Chronic Episodic Hypoxia

An improved strategy for evaluating the extent of chronic arterial baroreceptor denervation in conscious rats

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