Background:Somatic mutations affecting components of the Ras-MAPK pathway are a common feature of cancer, whereas germline Ras pathway mutations cause developmental disorders including Noonan, Costello, and cardio-facio-cutaneous syndromes. These ‘RASopathies' also represent cancer-prone syndromes, but the quantitative cancer risks remain unknown.Methods:We investigated the occurrence of childhood cancer including benign and malignant tumours of the central nervous system in a group of 735 individuals with germline mutations in Ras signalling pathway genes by matching their information with the German Childhood Cancer Registry.Results:We observed 12 cases of cancer in the entire RASopathy cohort vs 1.12 expected (based on German population-based incidence rates). This corresponds to a 10.5-fold increased risk of all childhood cancers combined (standardised incidence ratio (SIR)=10.5, 95% confidence interval=5.4–18.3). The specific cancers included juvenile myelomonocytic leukaemia=4; brain tumour=3; acute lymphoblastic leukaemia=2; rhabdomyosarcoma=2; and neuroblastoma=1. The childhood cancer SIR in Noonan syndrome patients was 8.1, whereas that for Costello syndrome patients was 42.4.Conclusions:These data comprise the first quantitative evidence documenting that the germline mutations in Ras signalling pathway genes are associated with increased risks of both childhood leukaemia and solid tumours.

(Ϫ)-Isoproterenol [4-[1-hydroxy-2-[(1-methylethyl)amino]ethyl]-1,2-benzene diol hydrochloride] relaxes murine detrusor through ␤-adrenoceptors (ARs); however, the ␤-AR subtypes involved are unknown. ␤ 2 -ARs have been associated with caveolae, plasmalemmal scaffolding domains that are absent in caveolin-1 (cav-1) knockout (KO) mice. Here, we studied detrusor responses in the absence and presence of ␤-AR subtype-selective antagonists in wild-type (WT) and cav-1 KO mice. To inquire whether the murine detrusor model is relevant to man, ␤-AR subtypes that mediate (Ϫ)-isoproterenol-evoked human detrusor relaxation were investigated. In WT mice, (Ϫ)-isoproterenol concentration-dependently relaxed the KCl (40 mM)-precontracted detrusor (ϪlogEC 50 M ϭ 8.04, E max ϭ 62%). The effects of (Ϫ)-isoproterenol were surmountably antagonized by the ␤ 2 -AR-selective antagonist ICI 118,551, suggesting involvement of ␤ 2 -AR only. The cav-1 KO detrusor displayed significant contractile dysfunction. (Ϫ)-Isoproterenol was less potent and efficient in relaxing detrusor from cav-1 KO (ϪlogEC 50 M, 7.76; E max ϭ 44%), but ICI 118,551 caused similar antagonism (pK B ϭ 9.15), suggesting that ␤ 2 -AR function persisted in cav-1 KO. The ␤ 3 -AR-selective antagonist L-748,337 in the presence of ICI 118,551 and CGP 20712 caused additional blockade of (Ϫ)-isoproterenol effects in cav-1 KO, consistent with a ␤ 3 -AR involvement during relaxation and suppression of this effect in WT. (Ϫ)-Isoproterenol relaxed human detrusor muscle precontracted with carbachol (ϪlogEC 50 M ϭ 6.39, E max ϭ 52%). However, the effects of (Ϫ)-isoproterenol in human detrusor were not blocked by CGP 20712 or ICI 118,551 but antagonized by L-748,337 (pK B ϭ 7.65). We conclude that murine detrusor relaxation occurs via ␤ 2 -AR, and loss of caveolae does not perturb ␤ 2 -AR function but unmasks an additional activation of ␤ 3 -AR. In contrast, detrusor relaxation in man is mediated exclusively via ␤ 3 -AR.In the lower urinary tract, adrenoceptors (ARs) are important for regulating detrusor contractile function and promoting urinary continence (Andersson and Arner, 2004;Michel and Vrydag, 2006). ␤-ARs mediate relaxation of bladder smooth muscle via stimulation of adenylyl cyclase and subsequent increase in cAMP. In rat and human detrusor, all three ␤-AR subtypes (␤ 1 -AR, ␤ 2 -AR, and ␤ 3 -AR) are expressed at the mRNA level (Matsubara et al., 2002;Nomiya and Yamaguchi, 2003). ␤-AR-mediated detrusor relaxation appears quite variable between different species; although similar maximal relaxant effects of (Ϫ)-isoproterenol are reported, the potency of (Ϫ)-isoproterenol varies. Moreover, different ␤-AR subtypes are involved in detrusor relaxation (Oshita et al., 1997;Yamazaki et al., 1998;Takeda et al., 2003), with, for instance, ␤ 2 -AR mediating relaxation in rabbit (Morita et al., 2000), ␤ 2 -AR and ␤ 3 -AR (Takeda et al., 2003;Uchida et al., 2005) or even all three subtypes in rat Article, publication date, and citation information can be found at

Large-conductance Ca2+-activated K+ channels (BK Ca or maxiK channels) are expressed in different cell types. They play an essential role in the regulation of various cell functions. In particular, BK Ca channels have been extensively studied in vascular smooth muscle cells, where they contribute to the control of vascular tone. They facilitate the feedback regulation against the rise of intracellular Ca2+, membrane depolarization and vasoconstriction. BK Ca channels promote a K+ outward current and lead to membrane hyperpolarization. In endothelial cells expression and function of BK Ca channels play an important role in the regulation of the vascular smooth muscle activity. Endothelial BK Ca channels modulate the biosyntheses and release of various vasoactive modulators and regulate the membrane potential. Because of their regulatory role in vascular tone, endothelial BK Ca channels have been suggested as therapeutic targets for the treatment of cardiovascular diseases. Hypertension, atherosclerosis, and diabetes are associated with altered current amplitude, open probability, and Ca2+-sensing of BK Ca channels. The properties of BK Ca channels and their role in endothelial and vascular smooth muscle cells would address them as potential therapeutic targets. Further studies are necessary to identify the detailed molecular mechanisms of action and to investigate selective BK Ca channels openers as possible therapeutic agents for clinical use.

Objectives• To elucidate the impact of the mucosa on detrusor muscle function by investigating force of contraction under various stimulatory conditions and during subsequent relaxation using catecholamines. Patients and Methods• Detrusor tissue was obtained from patients who had undergone cystectomy for bladder cancer and strips of intact or mucosa-denuded muscle were set up for force measurement. Preparations were precontracted with KCl, carbachol or electric-field stimulation (EFS).• Precontracted strips were relaxed using increasing concentrations of catecholamines in the absence and presence of the subtype-selective β-adrenoceptor (AR) blockers CGP 20712A (β1-ARs), ICI 118,551 (β2-ARs), and L-748,337 (β3-ARs). Results• Force development in response to KCl (40 mM), carbachol (1 μM) or EFS was larger in the absence of mucosa than in intact muscle strips. The force of contraction of mucosa-denuded strips with detached urothelium incubated in the same chamber was as low as in intact strips.• Noradrenaline relaxed precontracted detrusor strips to a significantly larger extent and at lower concentrations in denuded than in intact strips.• CGP 20712A did not affect noradrenaline-induced relaxation of denuded and intact strips, and ICI 118,551 did not influence noradrenaline-induced relaxation in denuded strips, but abolished the difference between denuded and intact strips.• The antagonism of the relaxant effects of noradrenaline by L-748,337 was slightly smaller in intact than denuded strips. Conclusions• The mucosa of human detrusor strips impairs force development when stimulated with KCl, carbachol or EFS.• The mucosa also blunts the relaxing effects of catecholamines. The latter effect does not involve the activation of β1-ARs but only of β2-ARs, whereas β3-ARs mediate the relaxation of human detrusor.

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.