Post-
transplantation thrombosis may occur in donor segments of iliac arteries and livers following surgical removal and storage in University of Wisconsin (
UW) solution for
transplantation. We have previously suggested that
purine receptors are vulnerable to denaturation after UW storage. The aims of the present study were to determine what particular subtypes of
purine P2Y receptors in rabbit thoracic aorta deteriorate after 8 days of UW storage by studying vascular reactivity to
acetylcholine,
ATP,
2MeSATP and
UTP. Ring segments of aortae from male New Zealand White rabbits were mounted upon fine-wire myographs and vasodilatation to the above agents tested on fresh tissue, and after 8 days of UW storage. Vasodilatation to
ATP was attenuated by 100 microM
L-NAME in fresh tissue suggesting that the relaxant response was, in part, due to
nitric oxide (NO). P2Y-mediated relaxation to
ATP was significantly attenuated by UW storage and
cholinergic responses were not. This attenuated relaxation to
ATP was not further attenuated by
L-NAME, suggesting a loss of the NO-dependent mechanism. De-endothelialisation indicated that
UTP-mediated vasorelaxation, via P2Y(2) receptors, was endothelium-dependent. Any residual endothelium-independent relaxation to
UTP was abolished by UW storage and endothelium-dependent
UTP relaxation was reduced to the same level as that seen in fresh, de-endothelialised tissue. In contrast responses to
2MeSATP, via P2Y(1) receptors, were predominantly endothelium-independent and were only partially attenuated by UW storage. Responses to pyridoxalphosphate-6-azophenyl-2('),4(')-disulphonic
acid (
PPADS) and
L-NAME suggested that vasorelaxation to
2MeSATP and
UTP was mediated by P2Y(1) and P2Y(2) receptors, respectively. It is therefore concluded that UW storage predominantly decreases P2Y(2) receptor-mediated vascular reactivity.