Background and purpose: Adrenoceptors can associate with cardiac caveolae. To investigate the function of vascular caveolae, adrenoceptor-mediated effects were compared in the saphenous artery of caveolin-1 knockout (cav-1KO) and wild-type (WT) mice. Experimental approach: Electronmicroscopy was used to detect caveolae. Real-Time quantitative PCR was used for adrenoceptor subtypes. Catecholamine-evoked contractions and relaxations were studied in arterial segments. Key results: Caveolae were found in arterial smooth muscle from WT but not from cav-1KO mice. Arterial mRNA levels for the adrenoceptors a 1A , a 1B , a 1D , b 1 , b 2 and b 3 were similar in cav-1KO and WT. (-)-Noradrenaline contracted cav-1KO (-log EC 50 M ¼ 7.1) and WT (-log EC 50 M ¼ 7.3) arteries through prazosin-sensitive receptors. Maximum (-)-noradrenalineevoked contractions were greater in cav-1KO than WT arteries. (-)-Isoprenaline relaxed WT arteries (-log EC 50 M ¼ 7.3) more potently than cav-1KO arteries (-log EC 50 M ¼ 6.8); the effects were antagonized partially and similarly by the b 2 -selective antagonist ICI118551 (50 nM). The (-)-isoprenaline-evoked relaxation was partially antagonized by the b 1 -adrenoceptorselective antagonist CGP20712 (300 nM) in WT but not cav-1KO arteries. The b 3 -adrenoceptor-selective antagonist L748337 (100nM) partially antagonized the relaxant effects of (-)-isoprenaline in cav-1KO but not in WT arteries. BRL37344 partially relaxed arteries through b 3 -adrenoceptors in cav-1KO but not WT. The relaxant effects of BRL37344 were decreased by the NO synthase inhibitor OL-nitroarginine. Conclusions and implications:The function of arterial a 1 -and b 2 -adrenoceptors is similar in cav-1KO and WT mice. b 1 -adrenoceptor-mediated relaxation in WT is lost in cav-1KO and replaced by the appearance of b 3 -adrenoceptors.