Disinhibition of the hypothalamic paraventricular nucleus increases mean circulatory filling pressure in conscious rats

Martin, Doug; Rodrigo, Manoj C.; Egland, M.C.; Barnes, Ludwig

doi:10.1016/s0006-8993(97)00128-5

Cited by 10 publications

(8 citation statements)

References 42 publications

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“…We chose to assess systemic venous tone by measuring the mean circulatory filling pressure (MCFP). We showed previously that MCFP is increased in settings of increased sympathetic drive (Martin et al, 1996;Martin et al, 2006;Martin et al, 1997), consistent with the view that the MCFP is a reliable estimate of systemic venous tone (Rothe, 1993).…”

Section: Discussionsupporting

confidence: 88%

Activation of bradykinin-sensitive pericardial afferents increases systemic venous tone in conscious rats

Martin

Vogel

Freeling

et al. 2020

Autonomic Neuroscience

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The venous system plays a critical role in blood pressure regulation by controlling venous return, cardiac filling, and cardiac output. Sympathetic drive is a major controller of venous function. However, outside of the arterial baroreflex, the mechanisms that regulate sympathetic drive to veins remain poorly defined in both physiological and disease conditions. The heart itself has an important sensory function via a variety of cardiac receptors that modulate cardiovascular function by neural and humoral reflexes. Bradykinin‐sensitive sympathetic afferent nerves from the heart can trigger marked increases in efferent sympathetic nerve activity to some cardiovascular target organs such as the kidney. This work tested the hypothesis that the activation of bradykinin‐sensitive cardiac afferents increases venous tone and cardiac output. Sprague Dawley rats were anesthetized with a cocktail of alpha chloralose (80 mg/kg) and urethane (800 mg/kg). Catheters were placed in the femoral artery and vein to record arterial and venous blood pressures. A PE 10 catheter was placed in the pericardial space for the injection of bradykinin (BK), an agent known to stimulate cardiac sympathetic afferents. In some rats, a balloon tipped catheter was placed in the right atrium to allow transient arrest of cardiac pumping for the estimation of mean circulatory filling pressure (MCFP), an estimate of systemic venous tone. In other rats, an electromagnetic flow probe was placed on the aortic arch for the direct measurement of cardiac output. In rats instrumented for the measurement of venous tone, pericardial injections of BK (0.4–20 μg/kg) were associated with dose‐related increases in mean arterial pressure (9±6 to 27±6 mm Hg) and MCFP (0.6±0.2 to 1.6±0.4 mm Hg). These responses were largely attenuated after ganglionic blockade. In rats instrumented for the measurement of cardiac output, pericardial injection of BK (10 μg/kg) increased mean arterial pressure (23±3 mm Hg) and cardiac output (16±2 ml/min). We interpret these data to indicate that activation of bradykinin‐sensitive pericardial afferents increases venous tone sufficiently to increase cardiac filling and cardiac output. Support or Funding Information Supported by NIH R01 HL136741‐01 and the Basic Biomedical Sciences program of the Sanford School of Medicine, University of South Dakota. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

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Section: Discussionsupporting

confidence: 88%

Activation of bradykinin-sensitive pericardial afferents increases systemic venous tone in conscious rats

Martin

Vogel

Freeling

et al. 2020

Autonomic Neuroscience

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“…In addition, we observed that the expression of CINC mRNA was highest around the periventricular area, which contains the paraventricular nucleus (PVN) of the hypothalamus. It has been suggested that the PVN of the hypothalamus is a site of integration of autonomic and endocrine cardiovascular responses (20). Indeed, the expression of CINC mRNA in the PVN has been shown to be increased by immobilization stress (11) and osmotic stimulation (21).…”

Section: Discussionmentioning

confidence: 99%

Involvement of Cytokine-Induced Neutrophil Chemoattractant in Hypothalamic Thermoregulation of Luteinizing Hormone-Releasing Hormone

et al. 2008

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We demonstrated in a previous study that serum IL-8 concentrations were significantly higher in women with hot flashes than without hot flashes. To clarify the role of IL-8 in the pathoetiology of menopausal hot flashes, we examined the effect of rat cytokine-induced neutrophil chemoattractant (CINC), a member of the IL-8 family, on thermoregulation using ovariectomized (OVX) rats treated with intracerebroventricular (i.c.v.) injection of LHRH agonist (LHRHa) as a model of hot flashes. We found that: 1) expression of CINC mRNA was increased around the periventricular area in the hypothalamus at 1 h, and the serum CINC concentration was increased at 2 h after i.c.v. injection of LHRHa; 2) the increase in serum CINC concentration in hypophysectomized rats was significantly lower than that in sham-operated rats; 3) i.c.v. but not iv injection of CINC elevated the rectal temperature of OVX rats; 4) i.c.v. injection of LHRHa into OVX rats produced a rapid rise (maximal increase: 10-25 min) in tail skin temperature, and the elevation was augmented by injection of an anti-CINC antibody; and 5) changes in serum CINC concentration and skin temperature after i.c.v. injection of LHRHa were reversed by replacement of estradiol. In conclusion, the production of CINC in the hypothalamus due to LHRHa injection in OVX rats was increased after elevation of skin temperature, suggesting that CINC plays a key role in the homeostasis of body temperature. Disturbance of the thermoregulatory mechanism involving LHRH and CINC may be related to the pathoetiology of hot flashes.

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“…12 Recently, in our laboratory, we have observed that interventions that raise MCFP by approximately 1 mm Hg are also associated with an increase in CO of approximately 10% to 15%. 26,32 Thus, changes in MCFP can have a significant impact on CO. In the present study, we observed a difference in MCFP that ranged from 1.2 to 1.7 mm Hg, which is of sufficient magnitude to have significantly elevated CO.…”

Section: Discussionmentioning

confidence: 99%

“…We have previously shown that use of the restrainers does not affect measurement of MAP or MCFP. 26 The arterial and venous catheters were connected to pressure transducers which led to an A/D system (Biopac Systems) that interfaced with a Macintosh microcomputer (Apple). Blood pressure signals were acquired at 50 Hz and recorded to disk.…”

Section: Protocolmentioning

confidence: 99%

Venous Tone in the Developmental Stages of Spontaneous Hypertension

1998

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Abstract-The initial stages of hypertension in the spontaneously hypertensive rat (SHR) are characterized by an increase in cardiac output. Venous capacitance plays an important role in the control of cardiac output. This study tested the hypothesis that venous tone is elevated in the developmental stages of spontaneous hypertension. Male SHR or normotensive Wistar-Kyoto (WKY) rats were instrumented for the measurement of arterial pressure (FAP) and intrathoracic vena caval pressure (FVP). A latex-tipped catheter was advanced into the right atrium via the jugular vein. Mean circulatory filling pressure (MCFP), an index of integrated venomotor tone, was calculated as MCFPϭFVPϩ(FAPϪFVP)/VAR. FAP and FVP were recorded after 5 seconds of right atrial balloon inflation. The venous to arterial compliance ratio (VAR) was estimated as 76 for WKY and 106 for SHR. Mean arterial pressure (MAP), heart rate, and MCFP were recorded in conscious rats of 4 to 6 and 8 to 10 weeks of age. In 4-to 6-week-old rats, both MAP and MCFP were significantly elevated in the SHR (MAP, 129Ϯ6 mm Hg; MCFP, 6.6Ϯ0.4 mm Hg) compared with the age-matched WKY (MAP, 91Ϯ6 mm Hg; MCFP, 5.4Ϯ0.4 mm Hg), whereas heart rate was not significantly different. The elevations in MAP (SHR, 144Ϯ4 mm Hg; WKY, 102Ϯ3 mm Hg) and MCFP (SHR, 7.7Ϯ0.3 mm Hg; WKY, 6.0Ϯ0.2 mm Hg) in SHR were exaggerated at 8 to 10 weeks of age. After ganglionic blockade (chlorisondamine; 10 mg/kg), the differences in MCFP were no longer statistically significant between SHR and WKY at both 4 to 6 weeks of age (3.9Ϯ0.2 versus 4.0Ϯ0.3 mm Hg) and 8 to 10 weeks of age (5.0Ϯ0.3 versus 4.3Ϯ0.3 mm Hg, respectively). The differences in MAP at 4 to 6 weeks of age (79Ϯ7 versus 67Ϯ5 mm Hg, respectively) also were not statistically significant after ganglionic blockade. However, a significant difference in MAP between strains remained after ganglionic blockade in 8-to 10-week-old rats (90Ϯ5 versus 63Ϯ3 mm Hg, respectively). These findings indicate that venous tone is increased via autonomic effector systems during the developmental stages of spontaneous hypertension. These data also suggest that autonomic mechanisms predominate at very early stages, whereas nonautonomic mechanisms assume more importance in maintaining the elevated MAP as hypertension progresses. (Hypertension. 1998;31[part 1]:139-144.)

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Disinhibition of the hypothalamic paraventricular nucleus increases mean circulatory filling pressure in conscious rats

Cited by 10 publications

References 42 publications

Activation of bradykinin-sensitive pericardial afferents increases systemic venous tone in conscious rats

Activation of bradykinin-sensitive pericardial afferents increases systemic venous tone in conscious rats

Involvement of Cytokine-Induced Neutrophil Chemoattractant in Hypothalamic Thermoregulation of Luteinizing Hormone-Releasing Hormone

Venous Tone in the Developmental Stages of Spontaneous Hypertension

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