The acute increases in vasomotor tone and blood pressure induced by carotid artery occlusion are modulated by platelet-activating factor (PAF) independently of nitric oxide release

Lopes-Martins, Rodrigo Álvaro Brandão; Estato, Vanessa; Araujo, Claudia V. de; Catelli, Marcelo Flores; Cordeiro, Renato S.B.; Tibiriçá, Eduardo

doi:10.1016/s0929-7855(97)00025-4

Cited by 2 publications

(3 citation statements)

References 48 publications

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“…In previous studies, we have already provided strong evidence that PAF has a physiological role in the regulation of the cardiovascular system, specifically in modulating systemic vascular resistance in the anaesthetised rabbit (Lopes-Martins et al 1996, 1997. Thus, in the present study we used similar pharmacological approaches in order to blunt the potential effects of endogenously released PAF on renal vascular reactivity: blockade of PAF cellular effects using specific PAF receptor antagonists and inhibition of PAF biosynthesis with mepacrine, which is a phospholipase A 2 (PLA 2 ) inhibitor.…”

Section: Discussionmentioning

confidence: 96%

“…Recently, using the experimental model of the anaesthetised rabbit, we provided pharmacological evidence that PAF has a physiological role in the regulation of the cardiovascular function, specifically in the modulation of vascular resistance and, hence, of arterial pressure and blood flow (Lopes-Martins et al 1996, 1997. These results suggest that PAF could be released following acute increases in blood pressure, with this mediator then acting via a negative feedback mechanism which downregulates vascular smooth muscle tone (Lopes-Martins et al 1996).…”

Section: Introductionmentioning

confidence: 97%

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Involvement of platelet-activating factor in the modulation of vascular tone in the isolated perfused rabbit kidney

Cailleaux¹,

Lopes-Martins²,

Aimbire³

et al. 1999

Naunyn-Schmiedeberg's Arch Pharmacol

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The hypothesis that platelet-activating factor (PAF) plays a role in the modulation of the vasomotor tone and blood pressure was put forward by our group in previous in vivo studies in anaesthetised rabbits. The present study was undertaken to investigate the putative role of this lipid mediator in the vascular reactivity of the renal circulation, using the experimental model of the isolated perfused rabbit kidney. Dose-response curves to noradrenaline-induced vasoconstriction were performed before and after continuous infusions of two different PAF-receptor antagonists (WEB 2086 and yangambin) and of the phospholipase A2 inhibitor mepacrine. The increases in renal perfusion pressure elicited by noradrenaline were potentiated by all the above-mentioned treatments in a dose-dependent manner. Moreover, prostaglandin F2alpha-induced vasoconstriction was also potentiated by the administration of the PAF receptor antagonists and mepacrine. Furthermore, the administration of PAF into the renal circulation induced dose-related and long-lasting vasodilator responses, which were blocked by the PAF receptor antagonists. Nevertheless, PAF-induced renal vasodilation was also abolished by a pretreatment with mepacrine or with the cyclooxygenase inhibitor indomethacin, suggesting that it enhances the secondary formation of vasodilator arachidonic acid metabolites. The data indicate that PAF is involved in the modulation of the vasomotor tone in the renal circulation, through the release of cyclooxygenase products, constituting an additional mechanism of modulation of smooth muscle cell contractility to the ones exerted by well-known vasoactive substances of endothelial origin such as nitric oxide.

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Section: Discussionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 97%

Involvement of platelet-activating factor in the modulation of vascular tone in the isolated perfused rabbit kidney

Cailleaux¹,

Lopes-Martins²,

Aimbire³

et al. 1999

Naunyn-Schmiedeberg's Arch Pharmacol

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show abstract

“…[26] reported that the PAF‐induced vasodilation of in vitro perfused rabbit renal afferent arterioles preconstricted by noradrenaline was not abolished by NO synthase inhibitors. In addition, previous studies from our group suggested the involvement of PAF in a negative feedback mechanism effective in the local regulation of vasomotor tone in anaesthetized rabbits, but exclude the participation of NO in this process [27].…”

Section: Discussionmentioning

confidence: 99%

Antihypertensive effects of crude extracts from leaves of Echinodorus grandiflorus

Lessa

Araujo

Kaplan

et al. 2008

Fundamemntal Clinical Pharma

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The antihypertensive action of a crude ethanolic extract (EEEG) from leaves of Echinodorus grandiflorus (Alismataceae) was investigated in spontaneously hypertensive rats. The intraperitoneal injection of increasing doses of EEEG (300-1000 mg/kg) elicited dose-dependent reductions in mean arterial pressure (MAP) that were paralleled by reductions of cardiac output and systemic vascular resistance, reaching the maximum of 23 +/- 5%, 13 +/- 3% and 18 +/- 4%, respectively (n = 5, P < 0.05). Comparable reductions of MAP were obtained upon i.v. administration of EEEG (3-100 mg/kg), reaching the maximum decrease of 51 +/- 6% (n = 7; P < 0.001). The blockade of nitric oxide synthesis significantly reduced the hypotension induced by i.v. administration of EEEG. Moreover, the pre-treatment of the animals with a selective antagonist of cholinergic muscarinic receptors or of platelet-activating factor (PAF) receptors partially blunted the cardiovascular effects of EEEG. The i.v. pre-treatment with the selective B(2) bradykinin receptor antagonist HOE 140 or with indomethacin, an inhibitor of the enzyme cyclooxygenase, did not prevent the hypotensive effects induced by EEEG. Finally, the chronic oral treatment with EEEG presented a significant antihypertensive effect that was comparable to that of reference antihypertensive drugs currently used to treat arterial hypertension. It is concluded that EEEG elicits significant acute antihypertensive effects through the release of nitric oxide and the stimulation of cholinergic muscarinic and PAF receptors. Moreover, our results suggest that EEEG may be appropriate to chronic oral treatment of arterial hypertension.

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The acute increases in vasomotor tone and blood pressure induced by carotid artery occlusion are modulated by platelet-activating factor (PAF) independently of nitric oxide release

Cited by 2 publications

References 48 publications

Involvement of platelet-activating factor in the modulation of vascular tone in the isolated perfused rabbit kidney

Involvement of platelet-activating factor in the modulation of vascular tone in the isolated perfused rabbit kidney

Antihypertensive effects of crude extracts from leaves of Echinodorus grandiflorus

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