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

• Autorzy: Jochem J. , Zwirska-Korczala K. , Zabielski R. , Kato I. , Kuwahara A.
• Języki publikacji: EN

Abstrakty

EN

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.

Słowa kluczowe

EN

cardiovascular effect; orexin-A; hemorrhagic shock; rat; intracerebroventricular administration; arterial pressure; heart rate; normotension; hemorrhagic effect; sympathetic nervous system

• Wydawca: -
• Czasopismo: Journal of Physiology and Pharmacology. Supplement
• Rocznik: 2006
• Tom: 57
• Numer: 11
• Opis fizyczny: p.115-124,fig.,ref.

Twórcy

autor

Jochem J.

• Medical University of Silesia, H. Jordana 19, 41-808 Zabrze, Poland

autor

Zwirska-Korczala K.

autor

Zabielski R.

autor

Kato I.

autor

Kuwahara A.