Effects of Adenosine and Its Analogues on Isolated Internal Carotid Arteries from Newborn and Adult Pigs

Laudignon, N; Aranda, Jacob V.; Varma, Daya R.

doi:10.1159/000243238

Cited by 11 publications

(10 citation statements)

References 16 publications

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“…In order to block adenosine receptors we used 8-PT, a xanthine derivative that is more effective than theophylline (Williams, 1989) and does not have the inhibitory effect on phosphodiesterase activity, or other non-specific effects of theophylline (Smellie, Davis, Daly & Wells, 1979). Given at 8 mg kg-' as in the present study, 8-PT remained at a stable concentration in plasma of newborn piglets for at least 1 h (Laudignon et al 1990). Certainly, responses evoked by 2-CA were still blocked at the end of our experiments, -1 h after giving 8-PT.…”

Section: Responses Evoked In Newborn Pigletssupporting

confidence: 59%

Postnatal development of the pattern of respiratory and cardiovascular response to systemic hypoxia in the piglet: the roles of adenosine.

Elnazir

Marshall

Kumar

1996

The Journal of Physiology

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1. In 3-day-old and 3-week-old spontaneously breathing piglets anaesthetized with Saffan, we have studied ventilatory and cardiovascular responses evoked by 5 min periods of hypoxia (breathing 10 and 6% 02). 2. In 3-day-old piglets both 10 and 6% 02 evoked an increase followed by a secondary fall in ventilation, a gradual tachycardia and a renal vasoconstriction, with an increase in femoral blood flow that was attributable to femoral vasodilatation. Arterial blood pressure rose initially but fell towards control values by the 5th minute of hypoxia.3. The stable adenosine analogue 2-chloroadenosine (2-CA; 30 mg kg-' i.v.) evoked bradycardia and renal vasoconstriction, but had no effect on femoral vasculature. These responses were blocked by the adenosine receptor antagonist 8-phenyltheophylline (8-PT; 8 mg kg-1 i.v.). 8-PT also abolished the secondary fall in ventilation evoked by 10 and 6% 02 and the renal vasoconstriction evoked by 10 % 02, but had no effect on the tachycardia, or on the femoral vascular response. 4. By contrast, in 3-week-old piglets both 10 and 6% 02 evoked a sustained increase in ventilation, tachycardia and a rise in arterial pressure with renal vasoconstriction, but no change in renal blood flow and substantial femoral vasodilatation with an increase in femoral blood flow. 2-CA evoked bradycardia and renal vasoconstriction, as in 3-day-old piglets, but also evoked pronounced femoral vasodilatation. 8-PT blocked these responses and the hypoxia-induced femoral vasodilatation, but had no significant effect on other components of the hypoxia-induced response. 5. We propose that there is postnatal development of the ventilatory and cardiovascular responses evoked by systemic hypoxia and of the role of locally released adenosine in these responses: at 3 days, adenosine released within the central nervous system and within the kidney is a major contributor to the secondary fall in ventilation and renal vasoconstriction, respectively, whereas at 3 weeks, adenosine makes little contribution to the ventilatory response, or renal vasoconstriction, but is largely responsible for hypoxia-induced vasodilatation in skeletal muscle.

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Section: Responses Evoked In Newborn Pigletssupporting

confidence: 59%

Postnatal development of the pattern of respiratory and cardiovascular response to systemic hypoxia in the piglet: the roles of adenosine.

Elnazir

Marshall

Kumar

1996

The Journal of Physiology

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“…First, it should be noted that in Group 1, the increase in FVC evoked by hypoxia and adenosine were similar as we intended, whereas the increases in FVC evoked by adenosine infusion in Groups 2 and 3 were substantially smaller than those evoked by hypoxia, even though we infused adenosine at the same dose per kilogram body weight. This may reflect the fact that the rats of Groups 2 and 3 were substantially younger than those of Group 1: there is evidence that dilator responsiveness to adenosine is weak or absent in neonates and increases with maturity (Laudignon et al 1990; Elnazir et al 1996). Second, in Group 2, the selective A 1 receptor antagonist DPCPX, decreased the muscle vasodilator response evoked by hypoxia by only ∼30%, whereas in most of our previous studies, ∼50% of the hypoxia‐induced muscle dilatation was mediated by adenosine and/or by A 1 receptor stimulation (e.g.…”

Section: Discussionmentioning

confidence: 99%

Measurement of nitric oxide release evoked by systemic hypoxia and adenosine from rat skeletal muscle in vivo

Ray¹,

Marshall²

2005

The Journal of Physiology

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It is accepted that NO plays a role in hypoxic vasodilatation in several tissues. For rat hindlimb muscle there is evidence that during systemic hypoxia endogenously released adenosine acts on endothelial A 1 receptors to evoke dilatation in a NO-dependent fashion, implying requirement for, or mediation by, NO. We tested in vivo whether systemic hypoxia and adenosine release NO from muscle. In anaesthetized rats, arterial blood pressure (ABP) and femoral blood flow ( . These results allow the novel conclusion that the muscle vasodilatation of systemic hypoxia is partly mediated by adenosine acting at endothelial A 1 receptors to stimulate synthesis and release of NO, which then induces dilatation.

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“…Adenosine is also a vasodilator in internal carotid arteries of adult pigs but is less effective at eliciting vasodilatation in newborn pigs (Laudignon et al, 1990). The ability of adenosine to release NO and cause vasodilation in the carotid artery and its circulation was shown to be greater in mature than in juvenile or middle-aged rats (Omar and Marshall, 2010).…”

Section: K Carotid Arterymentioning

confidence: 99%

Purinergic Signaling and Blood Vessels in Health and Disease

2013

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Effects of Adenosine and Its Analogues on Isolated Internal Carotid Arteries from Newborn and Adult Pigs

Cited by 11 publications

References 16 publications

Postnatal development of the pattern of respiratory and cardiovascular response to systemic hypoxia in the piglet: the roles of adenosine.

Postnatal development of the pattern of respiratory and cardiovascular response to systemic hypoxia in the piglet: the roles of adenosine.

Measurement of nitric oxide release evoked by systemic hypoxia and adenosine from rat skeletal muscle in vivo

Purinergic Signaling and Blood Vessels in Health and Disease

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