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Centrally applied vasopressin intensifies hypotension and bradycardia after hemorrhage in SHR rats

100%

Dobruch J., Paczwa P., Lon S., Szczepanska-Sadowska E.

Journal of Physiology and Pharmacology

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2002

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tom 53

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nr 2

Spontaneuosly hypertensive rats (SHR) have been shown to exhibit several alterations in function of the intrabrain vasopressinergic system. The present study was designed to find out whether centrally administered vasopressin (AVP) may influence the cardiovascular adaptation to hypotensive hypovolemia in SHR rats. Two series of experiments were performed on conscious 17 SHR rats chronically implanted with lateral cerebral ventricle (LCV) cannulas and with femoral artery catheters. Mean arterial pressure (MAP) and heart rate (HR) were monitored before and after arterial bleeding (1,3% body weight) performed during LCV infusion of 1) artificial cerebrospinal fluid 5µl/hour (aCSF); and 2) arginine vasopressin, 100ng/hour/5µl of aCSF (AVP). Central administration of aCSF and AVP had no effect on MAP and HR under resting conditions. Hemorrhage evoked significant hypotension (p<0.001) and bradycardia (p<0.001). During central infusion of AVP hemorrhage resulted in significantly greater hypotension than during central infusion of aCSF alone (p<0,05). The results provide evidence that centrally applied vasopressin significantly modulates cardivascular adjustments to hypotensive hemorrhage in SHR.

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Effect of Endothelin-3 on blood pressure in conscious spontaneously hypertensive [SHR] and DOCA-salt hypertensive rats

100%

Januszewicz A., Lon S., Lapinski M., Stys A.

Journal of Physiology and Pharmacology

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1994

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tom 45

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nr 1

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Hypotensive function of the brain angiotensin-[1-7] in sprague dawley and renin transgenic rats

88%

Dobruch J., Paczwa P., Lon S., Khosla M. C., Szczepanska-Sadowska E.

Journal of Physiology and Pharmacology

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2003

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tom 54

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nr 3

Angiotensin-(1-7) (Ang-[1-7]) is present in the brain of normotensive Sprague Dawley (SD) rats, and its hypothalamic content is elevated in TGRmRen2(27) rats (TGR) with renin dependent transgenic hypertension. The purpose of the present study was to determine the role of intrabrain Ang-(1-7) in the regulation of cardiovascular functions in SD and TGR rats under resting conditions and during haemodynamic challenge produced by rapid bleeding. Two groups of experiments were performed on conscious SD and TGR rats that were chronically instrumented with a lateral cerebral ventricle (LCV) cannula and an intraarterial catheter. Blood pressure (MAP) and heart rate period (Hp = distance between two systolic peaks) were continuously monitored: 1) under resting conditions during an LCV infusion of either artificial cerebrospinal fluid (aCSF, 5µl/hr) or Ang-(1-7) in aCSF (100 pmol/5µl/hr), and 2) before and after haemorrhage performed during LCV infusion of either aCSF or Ang-(1-7) antagonist (A-779, 4nmol/5µl/hr). Cerebroventricular infusion of Ang-(1-7) did not affect baseline MAP in the SD rats but it caused a significant decrease in blood pressure in the TGR rats. In the control experiments, haemorrhage significantly reduced MAP in the SD and TGR rats and heart rate in the TGR rats. Cerebroventricular infusion of Ang-(1-7) antagonist eliminated posthaemorrhagic hypotension in both strains and bradycardia in the TGR rats. The results indicate that intrabrain Ang-(1-7) may contribute to posthaemorrhagic hypotension and bradycardia. Moreover, the manner in which it centrally regulates the cardiovascular functions in the SD and TGR rats may be considerably different.

Ograniczanie wyników

3 Journal of Physiology and Pharmacology

3 Lon S.

2 Dobruch J.

2 Paczwa P.

2 Szczepanska-Sadowska E.

1 Januszewicz A.

1 Khosla M. C.

1 Lapinski M.

1 Stys A.

1 2003

1 2002

1 1994

Centrally applied vasopressin intensifies hypotension and bradycardia after hemorrhage in SHR rats

Effect of Endothelin-3 on blood pressure in conscious spontaneously hypertensive [SHR] and DOCA-salt hypertensive rats

Hypotensive function of the brain angiotensin-[1-7] in sprague dawley and renin transgenic rats