Background: Chronic diabetes is associated with alterations in autonomic modulation of the cardiovascular system. Although the rat has been used extensively in studies of experimental diabetes, there have been no reports on the changes in autonomic modulation of the cardiovascular function in chronic diabetic rats.
Objective: To examine chronic diabetic rats to determine the autonomic modulation of arterial pressure and heart rate variabilities in the time and frequency domain.
Materials And Methods: Diabetes was induced in rats by a single injection of streptozotocin, and 30 min of pulsatile arterial pressure was recorded in conscious rats, 5, 10-20 days and 12-18 weeks after the streptozotocin injection. Control rats were injected with vehicle. Beat-by-beat systolic arterial pressure and heart rate were obtained from pulsatile pressure. The spectral density powers of systolic arterial pressure and heart rate were calculated using fast Fourier transformation, and integrated in low-(0.015-0.25 Hz), mid- (0.25-0.75 Hz) and high- (0.75-3.0 Hz) frequency bands. The standard deviations of systolic arterial pressure and heart rate were also calculated.
Results: Basal systolic arterial pressure and heart rate were reduced in diabetic animals studied 10-20 days and 12-18 weeks after the streptozotocin injection. The standard deviations of systolic arterial pressure and heart rate were also reduced in the chronically diabetic animals. Diabetes reduced low- and mid-frequency variability but not the high-frequency variability of systolic arterial pressure. The low-frequency variability, but not the mid-frequency variability, of the heart rate was also reduced, while the high-frequency variability of the heart rate was reduced in the more chronically diabetic rats.
Conclusion: Our findings that the mid-frequency band variability of arterial pressure was reduced in diabetic patients suggest that sympathetic modulation of the cardiovascular system is impaired, corroborating other studies in such patients using this and other approaches.
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http://dx.doi.org/10.1097/00004872-199917040-00006 | DOI Listing |
Intensive Care Med Exp
January 2025
Department of Emergency Medicine in Linköping, and Department of Biomedical and Clinical Sciences, Linköping University, 582 25, Linköping, Sweden.
Background: This study aimed to investigate whether changes in capillary refill (CR) time precede macrovascular signs of deterioration in a human model of blood loss shock. The study was conducted at the Department of Emergency Medicine in Linköping, Sweden, and involved 42 healthy volunteers aged 18-45. Participants were randomized into two provocations of applied lower body negative pressure (LBNP): a stepwise escalation protocol and a direct application protocol, to simulate gradual and acute blood loss.
View Article and Find Full Text PDFCardiovasc Interv Ther
January 2025
Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, Fukuoka, Japan.
Advances in chronic thromboembolic pulmonary hypertension (CTEPH) treatment have improved prognosis, shifting focus towards symptom management. This study aimed to identify factors influencing the World Health Organization functional class (WHO-FC) in CTEPH patients. The CTEPH AC registry is a prospective, multicenter database from 35 Japanese institutions, analyzing data from August 2018 to July 2023.
View Article and Find Full Text PDFMed Klin Intensivmed Notfmed
January 2025
University Heart Center Lübeck, Department of Cardiology, Angiology and Intensive Care Medicine, University of Lübeck, German Center for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
Background: Pulmonary arterial embolism (PE) is not well characterized in elderly patients. In addition, unnecessary computed tomography pulmonary angiography (CTPA) examinations are often performed within this patient group, especially if the pretest probability is low.
Objective: To identify differences in clinical presentation in patients aged ≥80 years compared to patients <80 years and the effect of a BGA-optimized pretest probability to reduce unnecessary CTPAs according to age category.
J Exp Biol
January 2025
Department of Zoology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Peripheral arterial chemoreceptors monitor the levels of arterial blood gases and adjust ventilation and perfusion to meet metabolic demands. These chemoreceptors are present in all vertebrates studied to date but have not been described fully in reptiles other than turtles. The goals of this study were to 1) identify functional chemosensory areas in the South American rattlesnake (Crotalus durissus) 2) determine the neurochemical content of putative chemosensory cells in these areas and 3) determine the role each area plays in ventilatory and cardiovascular control.
View Article and Find Full Text PDFHypertension
January 2025
Department of Environmental Health, Life Science and Human Technology, Nara Women's University, Japan.
Background: Exposure to cold environments is linked to cold-induced hypertension due to activated sympathetic nerve activity (SNA) and arterial baroreceptor reflex dysfunction. However, direct measurement of SNA during cold-induced hypertension and changes in baroreflex control of SNA remain unexplored.
Methods: Chronically instrumented rats were exposed to cold temperatures (10 °C) over 4 days after a control period (24 °C), and renal and lumbar sympathetic nerve activities were simultaneously measured during cold-induced hypertension.
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