P2X(1) receptor-mediated pressor responses in the anesthetized mouse

P2X(1) receptors and adrenoceptors are mainly responsible for vasoconstriction in a variety of blood vessels. However, previous studies have shown that alpha,beta-methylene adenosine 5'-triphosphate (alpha,beta-MeATP), a stable analogue of ATP, can induce both pressor and depressor responses in laboratory animals. In this study, the effects of increasing intravenous doses of alpha,beta-MeATP and noradrenaline (NA) (0-30 nmol/kg) administered at 20 min intervals on systolic (SBP), diastolic (DBP) and mean (MBP) blood pressure in groups of anesthetized mice (n=6) were compared. Both alpha,beta-MeATP and NA caused transient, dose-dependent increases in SBP, DBP and MBP but the effect of alpha,beta-MeATP was more rapid and significantly larger at doses of 10 and 30 nmol/kg (P<0.01). At the dose of 30 nmol/kg, alpha,beta-MeATP increased SBP, DBP and MBP by 65.8 +/- 7.0, 65.7 +/- 5.0 and 65.7 +/- 5.5 mmHg, respectively, compared to increases of 36.8 +4.6, 33.3 +/- 4.9 and 34.5 +/- 4.7 mmHg, respectively, produced by NA. These results indicate P2X1 receptors play an important role in BP regulation although purinergic vasoconstriction alone may not explain the more potent pressor response to alpha,beta-MeATP in the anesthetized mouse. (C) 2012 Institute of Materia Medica, Chinese Academy of Medical Sciences and Chinese Pharmaceutical Association. Production and hosting by Elsevier B.V. All rights reserved.