Aldosterone regulates blood pressure (BP) through water and sodium balance. In our study, we studied if continuous treatment with a mineralocorticoid receptor antagonist, spironolactone (30 mg/kg/day) for 20 days can: 1) attenuate hypertension development and restore inverted 24-h BP rhythm in hypertensive transgenic (mRen-2)27 rats (TGR) measured by telemetry; 2) improve function of the kidneys and heart; 3) be protective against high salt load (1% in water) by mitigating oxidative injury and improving kidney function. Spironolactone decreased albuminuria and 8-isoprostane in normal and salt load conditions in BP-independent effects. Salt load increased BP, impaired autonomic balance, suppressed plasma aldosterone level and increased natriuresis, albuminuria and oxidative injury in TGR. Spironolactone did not restore the inverted 24-h rhythm of BP in TGR, therefore, mineralocorticoids are not crucial in regulation of BP daily profile. Spironolactone improved kidney function, decreased oxidative stress and was protective against high salt load in the BP-independent manner.
- MeSH
- albuminurie MeSH
- aldosteron * farmakologie MeSH
- antagonisté mineralokortikoidních receptorů farmakologie MeSH
- geneticky modifikovaná zvířata MeSH
- hypertenze * MeSH
- krevní tlak MeSH
- krysa rodu rattus MeSH
- ledviny MeSH
- receptory mineralokortikoidů genetika MeSH
- spironolakton farmakologie MeSH
- voda farmakologie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
NEW FINDINGS: What is the central question of this study? Artificial light at night decreases blood pressure and heart rate in rats. Are these changes in heart rate accompanied by changes in protein expression in the heart's left ventricle? What is the main finding and its importance? Five weeks of artificial light at night affected protein expression in the heart's left ventricle in normotensive and hypertensive rats. Artificial light at night decreased expression of the sarco/endoplasmic reticulum Ca2+ -ATPase, angiotensin II receptor type 1 and endothelin-1. ABSTRACT: Artificial light at night (ALAN) affects the circadian rhythm of the heart rate in normotensive Wistar rats (WT) and spontaneously hypertensive rats (SHR) through the autonomic nervous system, which regulates the heart's activity through calcium handling, an important regulator in heart contractility. We analysed the expression of the sarco/endoplasmic reticulum Ca2+ -ATPase (SERCA2) and other selected regulatory proteins involved in the regulation of heart contractility, angiotensin II receptor type 1 (AT1 R), endothelin-1 (ET-1) and tyrosine hydroxylase (TH), in the left ventricle of the heart in WT and SHR after 2 and 5 weeks of ALAN with intensity 1-2 lx. Expression of SERCA2 was decreased in WT (control: 0.53 ± 0.07; ALAN: 0.46 ± 0.10) and SHR (control: 0.72 ± 0.18; ALAN: 0.56 ± 0.21) after 5 weeks of ALAN (P = 0.067). Expression of AT1 R was significantly decreased in WT (control: 0.51 ± 0.27; ALAN: 0.34 ± 0.20) and SHR (control: 0.38 ± 0.07; ALAN: 0.23 ± 0.09) after 2 weeks of ALAN (P = 0.028) and in SHR after 5 weeks of ALAN. Expression of ET-1 was decreased in WT (control: 0.51 ± 0.27; ALAN: 0.28 ± 0.12) and SHR (control: 0.54 ± 0.10; ALAN: 0.35 ± 0.23) after 5 weeks of ALAN (P = 0.015). ALAN did not affect the expression of TH in WT or SHR. In conclusion, ALAN suppressed the expression of SERCA2, AT1 R and ET-1, which are important for the regulation of heart contractility, in a strain-dependent pattern in both WT and SHR.
- MeSH
- endoplazmatické retikulum metabolismus MeSH
- hypertenze * MeSH
- krevní tlak MeSH
- krysa rodu rattus MeSH
- potkani Wistar MeSH
- srdeční komory * MeSH
- světelné znečištění MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Prístrojové potápanie vyvoláva v organizme mnoho fyziologických zmien, najmä v kardiovaskulárnom, respiračnom a nervovom systéme. Vzhľadom na technické obmedzenia pri pobyte človeka pod vodnou hladinou, resp. v hyperbarickom prostredí, sa výskumné aktivity prevažne uskutočňujú pred a po ponore, čo značne limituje naše vedomosti o zmenách prebiehajúcich v reálnom čase v organizme potápača počas ponoru. Cieľom projektu bolo otestovať možnosti telemetrického sledovania potkanov počas ponorov v experimentálnej hyperbarickej komore. V našej práci sme zistili, že je možné telemetricky merať srdečnú variabilitu u potkanov počas ponorov do pabs 300 kPa. Pilotné výsledky naznačujú, že kyslík zohráva kľučovú úlohu v prispôsobení sa organizmu hyperbarickej hyperoxii.
SCUBA diving is associated with significant changes in human physiology. The most influenced organ systems are the cardiovascular, respiratory and nervous system. Traditionally, the diver is monitored pre and post dive, since environmental conditions while diving represents the main technological constraints for real-time measurements. These, together with the complexity of triggered physiological changes, limit our deep understanding of the effect of scuba diving on a diver’s physiology. The aim of this study was to develop and test telemetric measurement of heart rate and heart rate variability (HRV) in un-anesthetized conscious rats during experimental dives in the experimental hyperbaric chamber. Our pilot study showed the feasibility of telemetric measurement of heart rate and HRV up to pabs 300 kPa. Data indicate, that oxygen sensing might play a more significant role in cardiovascular adjustment to hyperbaric hyperoxia, however, more experiments are needed to fully understand underlying mechanisms.
- Klíčová slova
- hyperbarická komora,
- MeSH
- baroreflex MeSH
- hyperoxie * MeSH
- pilotní projekty MeSH
- potápění fyziologie MeSH
- potkani Wistar MeSH
- srdeční frekvence MeSH
- telemetrie MeSH
- určení tepové frekvence * metody MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
Under physiological conditions the mammalian circadian system is synchronized to a cyclic environment. The central oscillator in the suprachiasmatic nuclei (SCN) responds predominantly to an external light (L) dark (D) cycle. Peripheral oscillators are more efficiently synchronized by metabolic cues. When the circadian system is exposed to opposing synchronizing cues, peripheral oscillators uncouple from the SCN. To consider influence of phase advances and delays in light regimens mimicking shift work, we analyzed the expression of clock genes (per2, bmal1) and natriuretic peptides (anp, bnp) in the heart of male rats. Experimental groups were exposed to a rotating LD regimen with either 8 h phase advance or delay for 11 weeks. Samples were taken for a 24 h cycle in 4 h intervals. Peripheral oscillators responded to rotating phase advance by decreasing rhythm robustness, while phase delay mostly influenced the phase angle between the acrophase of rhythmic gene expression and the external LD cycle. The expression of anp was arrhythmic in the heart of control rats and was not influenced by rotating LD regimens. The expression of bnp showed a daily rhythm with a nadir during the active phase. The daily rhythm in bnp expression diminished under rotating LD regimen conditions.
- MeSH
- cirkadiánní proteiny Period metabolismus MeSH
- cirkadiánní rytmus * MeSH
- fotoperioda MeSH
- myokard metabolismus MeSH
- natriuretické peptidy metabolismus MeSH
- potkani Wistar MeSH
- transkripční faktory ARNTL metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Disturbed circadian activity of the sympathetic system may be involved in negative consequences of chronodisruption on the cardiovascular system. We studied daily changes in pressure response to adrenergic stimulation in rats exposed to repeated phase advance shifts (PAS) of light/dark (LD) regimen. Blood pressure (BP), heart rate (HR) and locomotor activity was measured by radiotelemetry in normotensive Wistar rats exposed to repeated PAS (three 8-h shifts per week) lasting for 12 weeks. Norepinephrine was administered subcutaneously in the middle of L and D during week 12 of PAS exposure. In the control LD cycle, cardiovascular parameters exhibited significant daily rhythms with expected higher values during D than L phase. Rats exposed to PAS showed disturbed rhythms without a BP and HR increase. Administration of norepinephrine to control rats revealed daily variability in the cardiovascular response with higher stimulation of BP during L than D. This daily pattern of BP response to norepinephrine was diminished in the PAS group. The damped daily variability in pressure response to norepinephrine and augmented response during the light phase of the day suggest that the increased and desynchronized activity of the sympathetic system may worsen responses of the cardiovascular system to load in individuals exposed to irregular LD conditions.
- MeSH
- časové faktory MeSH
- cirkadiánní rytmus * MeSH
- fotoperioda * MeSH
- injekce subkutánní MeSH
- krevní tlak účinky léků MeSH
- noradrenalin aplikace a dávkování farmakologie MeSH
- pohybová aktivita účinky léků MeSH
- potkani Wistar MeSH
- srdeční frekvence účinky léků MeSH
- světlo * MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
