Wyniki wyszukiwania

1

Inhibitory effect of Ca2+ on ATP-mediated stimulation of NPR-A-coupled guanylyl cyclase in renal glomeruli from spontaneously hypertensive and normotensive rats

100%

Woodard G. E., Zhao J., Rosado J. A.

Journal of Physiology and Pharmacology

|

2006

|

tom 57

|

nr 3

Atrial natriuretic peptide (ANP) regulates blood pressure mainly through the occupation of the guanylyl cyclase-coupled receptor NPR-A, which requires ATP interaction for maximal activation. This study investigates the effect of extracellular Ca2+ on ATP-mediated regulation of NPR-A-coupled guanylyl cyclase activity in glomerular membranes from Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR). ATP induced a significant increase in basal and ANP1-28-stimulated guanylyl cyclase activity that was greater in SHR than in WKY. Extracellular Ca2+ inhibited ATP-stimulated guanylyl cyclase activity in a concentration-dependent manner, but did not modify basal and ANP1-28-stimulated guanylyl cyclase activity. In the presence of ATP, NPR-A showed higher affinity for ANP1-28 and lower Bmax. Ca2+ did not modify NPR-A-ANP1-28 binding properties. The different effects of extracellular Ca2+ on ANP1-28- or ATP-mediated guanylyl cyclase activation suggest that these events are differentially regulated. Addition of extracellular Ca2+ induced similar effects in hypertensive and normotensive rats, suggesting that it is not responsible for the elevated cGMP production observed in SHR.

2

Changes in the vasoactive effects of nitric oxide, hydrogen sulfide and the structure of the rat thoracic aorta: the role of age and essential hypertension

84%

Berenyiova A., Drobna M., Cebova M., Kristek F., Cacanyiova S.

Journal of Physiology and Pharmacology

|

2018

|

tom 69

|

nr 4

3

Cardiovascular effects of centrally acting orexin A in haemorrhage-shocked rats

84%

Jochem J., Zwirska-Korczala K., Zabielski R., Kato I., Kuwahara A.

Journal of Physiology and Pharmacology. Supplement

|

2006

|

tom 57

|

nr 11

115-124

Orexin A influences the central cardiovascular regulation, since after intracerebroventricular (icv) administration it evokes short-lasting increases in mean arterial pressure (MAP) and heart rate (HR) in normotensive animals. The aim of the present study was to examine haemodynamic effects of orexin A in haemorrhage-shocked rats. Experiments were carried out in anaesthetized Wistar rats subjected for a critical irreversible haemorrhagic hypotension of 20-25 mmHg, which resulted in the death of all saline icv-treated control animals within 30 min. Orexin A (0.5-1.5 nmol; icv) administered at 5 min of critical hypotension evoked dose-dependent long-lasting increases in MAP, HR and renal, mesenteric and hindquarters blood flows, with a 100% survival of 2 h after treatment (1.5 nmol; icv). Changes in MAP and peripheral haemodynamics were inhibited by intravenous pretreatment with alpha1- and alpha2-adrenoceptor antagonists prazosin (0.5 mg/kg) and yohimbine (1.0 mg/kg), respectively. Moreover, both antagonists significantly decreased the survival rate to 16.6 and 33.3% (P<0.05 vs. orexin A [1.5 nmol]-treated group). In contrast, ß-adrenoceptor antagonist propranolol (1.0 mg/kg) completely blocked orexin A-induced HR changes, without influence on MAP, peripheral blood flows and the survival rate. Therefore, we conclude that centrally acting orexin A evokes the resuscitating effect in haemorrhage-shocked rats due to the activation of the sympathetic nervous system.

4

Moderate exercise training reduces arterial chemoreceptor reflex drive in mild hypertension

84%

Izdebska E., Izdebski J., Cybulska I., Makowiecka-Ciesla M., Trzebski A.

Journal of Physiology and Pharmacology. Supplement

|

2006

|

tom 57

|

nr 11

93-102

The aim of our study was to check the responsiveness the chemoreceptor reflex in 28 young mildly hypertensive men (HTS), aged 18-32 years and 25 normotensive male subjects (NTS) aged 19-32 years, before and after 3-months dynamic exercise training. We tested the hypothesis that dynamic training reduces arterial chemoreceptor drive in mild hypertension. Circulatory response to 3-min hyperoxic inactivation of arterial chemoreceptors induced by 70% oxygen breathing was measured before and after training. Arterial blood pressure (BP) was recorded continuously by Finapres method, stroke volume and arm blood flow were registered by impedance reography, heart rate by ECG. Both groups were submitted to moderate 3-months dynamic exercise training. Before training the hyperoxic breathing caused in HTS a significant decrease in systolic BP by 6±1mmHg p<0.01, in diastolic BP by 2±0.6mmHg p<0.01, and in total peripheral vascular resistance (TPR) by 0.24±0.04 TPRU (p<0.01). After training hyperoxia augmented systolic BP by 2.64±1.9mmHg (NS), diastolic BP by 2±1mmHg p<0.05, and TPR by 0.043±0.05 TPRU (ANOVA). In NTS before training brief hyperoxia produced insignificant change in BP and TPR. In NTS after training hyperoxia increased systolic BP by 4.2 mm Hg±1.23 p<0.01 and diastolic BP by 3.1±0.6mmHg p<0.01 respectively and TPR by 0.053±0.02 TPRU. Our results confirm earlier finding on the enhanced arterial chemoreceptor reflex drive in mild human hypertension. We conclude that normalizing arterial blood pressure in subjects with mild hypertension which occurred after 3-months dynamical exercise training is due to attenuation of the sympathoexcitatory chemoreceptor reflex drive by exercise training. The mechanism of this effect requires further study.

5

Contribution of neuronal nitric oxide (NO) synthase to N-acetylcysteine-induced increase of NO synthase activity in the brain of normotensive and hypertensive rats

84%

Pechanova O., Kunes J., Dobesova Z., Vrankova S., Zicha J.

Journal of Physiology and Pharmacology

|

2009

|

tom 60

|

nr 4

21-25

The goal of our study was to determine a contribution of nNOS to the increase of brain NO synthase activity induced by chronic N-acetylcysteine (NAC) treatment. Young 4-week-old male Wistar Kyoto rats (WKY) and spontaneously hypertensive rats (SHR) were subjected to treatment with NAC (1.5 g/kg/day) for 8 weeks. At the end of experiment total NOS activity was determined in the brainstem and cerebellum with and without specific nNOS inhibitor S-methyl-L-thiocitrulline (SMTC, 10-6 mol/l) by measuring the formation of L-[3H] citrulline from L-[3H] arginine. Chronic NAC treatment had no effect on blood pressure (BP) of WKY, while it attenuated BP increase in young SHR. Total NOS activity was increased in the brainstem of SHR compared to WKY, but this strain difference was abolished by SMTC. Chronic NAC treatment of SHR increased total NOS activity by 32% in the brainstem and by 67% in the cerebellum. After the incubation of brainstem and cerebellum with SMTC there were no significant differences in NOS activity of NAC-treated rats compared to strain-matched controls. Taken together, nNOS seems to be responsible for the increase of total NOS activity in the brain of SHR. SMTC inhibited 86% and 70% of NAC-induced increase of total NOS activity in the brainstem and cerebellum, respectively. Thus, nNOS is responsible not only for strain differences but also for NAC-induced increase of total NOS activity in the brain.

6

Propranolol modifies platelet serotonergic mechanisms in rats

84%

Zoltowski R., Pawlak R., Matys T., Pietraszek M., Buczko W.

Journal of Physiology and Pharmacology

|

2002

|

tom 53

|

nr 2

Though the mechanisms for the vascular actions of vasodilatory beta-blockers are mostly determined, some of their interactions with monoaminergic systems are not elucidated. Because there are evidences supporting a possible involvement of serotonin (5-HT) in the actions of beta-blockers, we studied the effect of propranolol on peripheral serotonergic mechanisms in normotensive and Goldblatt two-kidney - one clip (2K1C) hypertensive rats. In both groups of animals propranolol decreased systolic blood pressure, significantly increased whole blood serotonin concentration and at the same time it decreased platelet serotonin level. The uptake of the amine by platelets from hypertensive animals was lower than that of normotensive animals and it was decreased by propranolol only in the latter. In both groups propranolol inhibited potentiation of ADP - induced platelet aggregation by serotonin. In conclusion, this study provides evidence that propranolol modifies platelet serotonergic mechanisms in normotensive and renal hypertensive rats.

7

Long-term feeding with bioactive tripeptides in aged hypertensive and normotensive rats: special focus on blood pressure and bradykinin-induced vascular reactivity

67%

Siltari A., Roivanen J., Korpela R., Vapaatalo H.

Journal of Physiology and Pharmacology

|

2017

|

tom 68

|

nr 3

8

Effect of quercetin on kinetic properties of renal Na,K-ATPase in normotensive and hypertensive rats

67%

Mezesova L., Bartekova M., Javorkova V., Vlkovicova J., Breier A., Vrbjar N.

Journal of Physiology and Pharmacology

|

2010

|

tom 61

|

nr 5

The effect of quercetin, a plant-derived bioflavonoid with documented positive effect on the cardiovascular system, was examined after 4-week supplementation in the dose of 20 mg kg-1·day-1 to young male normotensive control (C) and to spontaneously hypertensive rats (SHR) over the period of their 5th-8th week of age. The study was focused on the influence of quercetin on properties of the renal Na,K-ATPase, a key system in maintaining the homeostasis of sodium in the organism. Spontaneous hypertension by itself enhanced the activity of Na,K-ATPase probably as a consequence of a higher number of active enzyme molecules, as suggested by the 15% increase of Vmax, along with improved affinity to ATP, as indicated by the 30% decrease in the value of Michaelis-Menten constant Km in untreated SHR vs. untreated normotensive rats. Quercetin induced a decrease of Na,K-ATPase activity in the presence of all ATP and Na+ concentrations investigated. Evaluation of kinetic parameters resulted in a constant Vmax value. The ATP-binding properties of the enzyme were not influenced by quercetin, as suggested by statistically insignificant changes in the value of Km both in controls and in SHR. On the other hand, the affinity to sodium decreased, as suggested by an increase in the KNa value by 22% and 31% in normotensive and hypertensive groups, respectively. This impairment in the affinity of the Na+-binding site of Na,K-ATPase molecules was probably responsible for the deteriorated enzyme function in the kidneys of quercetin treated animals.

9

Effect of chronic neuronal nitric oxide-synthase inhibition on arterial function and structure in spontaneously hypertensive rats

67%

Cacanyiova S., Kristek F., Malekova M., Ondrias K.

Journal of Physiology and Pharmacology

|

2012

|

tom 63

|

nr 1

10

Oxytocin in the cardiovascular responses to stress

67%

Wsol A., Cudnoch-Jedrzejewska A., Szczepanska-Sadowska E., Kowalewski S., Puchalska L.

Journal of Physiology and Pharmacology. Supplement

|

2008

|

tom 59

|

nr 8

11

Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik

Hemodynamic responses to brief hyperoxia in healthy and in mild hypertensive human subjects in rest and during dynamic exercise

67%

Izdebska E., Izdebski J., Trzebski A.

Journal of Physiology and Pharmacology

|

1996

|

tom 47

|

nr 2

Ograniczanie wyników

Inhibitory effect of Ca2+ on ATP-mediated stimulation of NPR-A-coupled guanylyl cyclase in renal glomeruli from spontaneously hypertensive and normotensive rats

Changes in the vasoactive effects of nitric oxide, hydrogen sulfide and the structure of the rat thoracic aorta: the role of age and essential hypertension

Cardiovascular effects of centrally acting orexin A in haemorrhage-shocked rats

Moderate exercise training reduces arterial chemoreceptor reflex drive in mild hypertension

Contribution of neuronal nitric oxide (NO) synthase to N-acetylcysteine-induced increase of NO synthase activity in the brain of normotensive and hypertensive rats

Propranolol modifies platelet serotonergic mechanisms in rats

Long-term feeding with bioactive tripeptides in aged hypertensive and normotensive rats: special focus on blood pressure and bradykinin-induced vascular reactivity

Effect of quercetin on kinetic properties of renal Na,K-ATPase in normotensive and hypertensive rats

Effect of chronic neuronal nitric oxide-synthase inhibition on arterial function and structure in spontaneously hypertensive rats

Oxytocin in the cardiovascular responses to stress

Hemodynamic responses to brief hyperoxia in healthy and in mild hypertensive human subjects in rest and during dynamic exercise