Pharmacological reactivity of neoplastic and non-neoplastic associated neovasculature to vasoconstrictors

摘要

Angiogenesis and the pharmacological responses of the tumour and non-tumour associated neovasculature have been investigated. Cannulated sponge discs in mice were used to host the angiogenic stimulators, while ¹³³Xe washout was employed to assess local blood flow. Enhancement of blood flow was detected in implants bearing B16 cells, 3T3 cells and angiotensin II (AII)-treated at day 7. The responses of non-neoplastic associated neovasculature at day 14 post sponge implantation to the vasoconstrictors used endothelin-1 (Et-1), AII, platelet activating factor (PAF) and 5-hydroxytryptamine (5-HT) were dose-dependent. By contrast, the newly formed blood vessels induced by tumour cells were markedly insensitive to the vasoconstrictors agonists Et-1 and AII, while fully responsive to PAF and 5-HT. The vessels resulting from neoplastic stimulus exhibited altered pharmacological reactivity, suggesting that the characteristics of the neovasculature are dependent on the nature of the angiogenic stimuli.