The effects of adenosine triphosphate (ATP) and related purines on human isolated subcutaneous and omental resistance arteries

Abstract

1Human resistance arteries were obtained from specimens of omentum and subcutaneous fat removed at surgery. They were studied in vitro by use of a myograph technique to determine the effects of purines on the arteries.2 In preparations where tone had been raised with noradrenaline, low concentrations (1 nM-1 gM) of adenosine triphosphate (ATP) and 2-methylthioATP, but not a,,-methyleneATP, produced concentration-dependent relaxation. There was a lack of relationship between the relaxation response to acetylcholine and that to ATP. 3 In preparations under basal tone, high concentrations (1 piM-1 mM) of ATP, 2-methylthioATP and a4,-methyleneATP produced concentration-dependent contractions. 4 The rank order of potency of the purine nucleotide analogues for the relaxation response was 2-methylthioATP > ATP > a4-methyleneATP and for the contractile response it was x,,BmethyleneATP > ATP = 2-methylthioATP. 5 Adenosine produced concentration-dependent relaxation in preparations under raised tone and was less potent than ATP but did not produce contraction in preparations at basal tone. Relaxation responses to adenosine, but not to ATP, were antagonized by 8-phenyltheophylline.6 These results indicate the presence of vasodilator P2Y-and P1-purinoceptors and vasoconstrictor P21-purinoceptors on human resistance arteries isolated from omental and subcutaneous sites.

Vasoconstriction in active skeletal muscles: a potential role for P2X purinergic receptors?

“…There is compelling evidence that ATP acts as a neurotransmitter in vascular smooth muscle and is coreleased with norepinephrine from sympathetic nerves (9,18,21,29). Burnstock and Kennedy (11) proposed the subdivision of P2 purinergic receptors into P2X, which mediate vasoconstriction, and P2Y, which mediate vasodilation.…”

“…blood flow; sympatholysis; autonomic nervous system; dogs FOR YEARS, SYMPATHETIC VASOCONSTRICTION has been thought to be mediated entirely by norepinephrine released from sympathetic nerve terminals. However, there is strong evidence that ATP acts as a neurotransmitter in vascular smooth muscle and is coreleased with norepinephrine from sympathetic nerves (9,18,21,29). The release of ATP is thought to stimulate a purinergic receptor (P2).…”

Purinergic Signaling and Blood Vessels in Health and Disease

“…There is evidence that degranulation of mast cells in the skin is produced by ATP released during antidromic impulses from sensory nerve endings during axon reflexes, leading to vasodilation of skin vessels (Kiernan, 1975). Human isolated subcutaneous resistance arteries were shown to dilate via P2Y and P1 receptors and constrict via P2X receptors (Martin et al, 1991). Intra-arterial infusion of ATP, ADP, and AMP in canine facial and nasal vascular Purinergic Signaling and Blood Vessels beds caused vasodilation (Bari et al, 1993).…”

Acidosis attenuates P2X purinergic vasoconstriction in skeletal muscle arteries

“…However, there is growing evidence that P2X purinergic receptors on vascular smooth muscle play an important role in vasoconstriction at rest and during exercise (4, 5). These receptors are activated by ATP, which is a cotransmitter released with norepinephrine from the sympathetic nerves (7,9,11,19).In the skeletal muscle vascular bed, physiological conditions (e.g., exercise) and pathological conditions (e.g., peripheral arterial insufficiency) cause a decrease in pH that may influence the regulation of vascular control (2, 13, 21). The pH sensitivity of adrenergic receptors in conduit arteries varies widely across vascular beds, but data suggest that the sensitivity of ␣ 2 -receptors is decreased with acidic pH (12,15,17).…”

“…However, there is growing evidence that P2X purinergic receptors on vascular smooth muscle play an important role in vasoconstriction at rest and during exercise (4, 5). These receptors are activated by ATP, which is a cotransmitter released with norepinephrine from the sympathetic nerves (7,9,11,19).…”