Effects of liposome-entrapped adenosine in the isolated rat aorta

This study examined the effects of adenosine- and adenosine deaminase-loaded liposomes upon the contractile activity of the vascular smooth muscle, using the isolated, de-endothelised rat aorta ring as in vitro model. While control liposomes had no effect, intraliposomal adenosine (5 × 10⁻³ M) induced contraction of the preparation. Intraliposomal adenosine deaminase induced partial relaxation of high K⁺-precontracted rings. The adenosine-induced contraction seems to involve Ca²⁺ influx through L-type channels as an essential component, but protein kinase C may also have a modulatory role.