Efeitos do estresse pelo frio sobre o tamanho nuclear do cardiomiócito em ratos: avaliação por microscopia de luz

Meneghini, Adriano; Ferreira, Celso; Abreu, Luíz Carlos de; Ferreira, Marcelo; Valenti, Vítor Engrácia; Murad, Neif

doi:10.1590/s0102-76382008000400013

Cited by 20 publications

(21 citation statements)

References 13 publications

(12 reference statements)

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“…It is well described that sympathetic activity is increased during stress conditions [2-4,29] and SHR is also a model to study hyperactivity and stress disorders [30,31]. The imbalance between sympathetic and parasympathetic components of the baroreflex in SHR is associated to their sympathetic hyperactivity.…”

Section: Discussionmentioning

confidence: 99%

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Cardiac baroreflex is already blunted in eight weeks old spontaneously hypertensive rats

Cisternas¹,

Valenti²,

Alves³

et al. 2010

Int Arch Med

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BackgroundThe literature did not evidence yet with which age spontaneously hypertensive rats (SHR) start to present baroreflex reduction. We endeavored to evaluate the baroreflex function in eight-week-old SHR.MethodsMale Wistar Kyoto (WKY) normotensive rats and SHR aged eight weeks were studied. Baroreflex was calculated as the variation of heart rate (HR) divided by the mean arterial pressure (MAP) variation (ΔHR/ΔMAP) tested with a depressor dose of sodium nitroprusside (SNP, 50 μg/kg) and with a pressor dose of phenylephrine (PHE, 8 μg/kg) in the right femoral venous approach through an inserted cannula in the animals. Significant differences for p < 0.05.ResultsBaseline MAP (p < 0.0001) and HR (p = 0.0028) was higher in SHR. Bradycardic peak was attenuated in SHR (p < 0.0001), baroreflex gain tested with PHE was also reduced in the SHR group (p = 0.0012). PHE-induced increase in MAP was increased in WKY compared to SHR (p = 0.039). Bradycardic reflex responses to intravenous PHE was decreased in SHR (p < 0.0001).ConclusionEight weeks old SHR already presents impairment of the parasympathetic component of baroreflex.

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Section: Discussionmentioning

confidence: 99%

“…These similarities include a genetic predisposition to high blood pressure with no specific etiology, increased total peripheral resistance without volume expansion and similar responses to drug treatment [1]. Moreover, cardiac hypertrophy, a stress model of heart disease [2-4] is another feature of SHR [5]. …”

Section: Introductionmentioning

confidence: 99%

Cardiac baroreflex is already blunted in eight weeks old spontaneously hypertensive rats

Cisternas¹,

Valenti²,

Alves³

et al. 2010

Int Arch Med

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“…The temperature was controlled by the refrigerated compartment. No rats died during the induced hypothermia procedure 6–8…”

Section: Methodsmentioning

confidence: 99%

“…Exposure to low temperatures is considered to be an important stressing physical agent 4,5. Previous studies have reported that acute exposure to cold stress can damage heart tissue6 and cause lipid depletion in the adrenal gland and glycogen depletion in the liver,6–8 thus suggesting that sympathetic activity and oxidative stress are the sources of these injuries.…”

Section: Introductionmentioning

confidence: 99%

“…Although it was recently indicated that cold stress induces glycogen and lipid depletion in the liver and the adrenal gland, respectively,6,14 no previous study has investigated the effects of different types of stress on the liver and the adrenal gland. Furthermore, it was previously observed that electrical discharge in rats was able to produce cardiac injury noted through mitochondrial impairment in the heart tissue;9–11 therefore, we hypothesized that an electrical discharge would also affect other organs in addition to the heart.…”

Section: Introductionmentioning

confidence: 99%

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Electric Countershock and Cold Stress Effects on Liver and Adrenal Gland

Ferreira

Abreu

Valenti

et al. 2010

Clinics

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OBJECTIVES:Cold exposure induces glycogen and lipid depletion in the liver and the adrenal gland, respectively. However, no previous study has determined the effects of electrical countershock on those tissues. We aimed to evaluate the effects of electrical countershock on lipid depletion in the adrenal gland and on glycogen depletion in the liver.METHODS:We used 40 male Wistar rats divided into four groups: the control group, in which the animals were subjected to a resting period of seven days; the electrical discharge group, in which the animals were subjected to a resting period followed by administration of ten 300-mV electrical discharges; the electrical post-discharge group, in which the animals received ten electrical shocks (300 mV) followed by rest for seven consecutive days; and the cold stress group, in which the animals were subjected to a resting period and were then exposed to −8ºC temperatures for four hours. All animals underwent a laparotomy after treatment. The lipid and glycogen depletions are presented using intensity levels (where + = low intensity and ++++ = high intensity, with intermediate levels in between).RESULTS:The rats exposed to the cold stress presented the highest glycogen and lipid depletion in the liver and the adrenal gland, respectively. Furthermore, we noted that the electrical countershock significantly increased lipid depletion in the adrenal gland and glycogen depletion in the liver. One week after the electrical countershock, the liver and adrenal gland profiles were similar to that of the control group.CONCLUSION:Electrical countershock immediately increased the glycogen depletion in the liver and the lipid depletion in the adrenal gland of rats.

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Excessive Activation of NMDA Receptors in the Pathogenesis of Multiple Peripheral Organs via Mitochondrial Dysfunction, Oxidative Stress, and Inflammation

Cheng

Chen

et al. 2020

SN Compr. Clin. Med.

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Efeitos do estresse pelo frio sobre o tamanho nuclear do cardiomiócito em ratos: avaliação por microscopia de luz

Cited by 20 publications

References 13 publications

Cardiac baroreflex is already blunted in eight weeks old spontaneously hypertensive rats

Cardiac baroreflex is already blunted in eight weeks old spontaneously hypertensive rats

Electric Countershock and Cold Stress Effects on Liver and Adrenal Gland

Excessive Activation of NMDA Receptors in the Pathogenesis of Multiple Peripheral Organs via Mitochondrial Dysfunction, Oxidative Stress, and Inflammation

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