Subjective well-being in schizophrenia: a randomised controlled open-label 12-month non-inferiority study comparing quetiapine XR with risperidone (RECOVER).

UNLABELLED: This randomised 12-month open study analysed the effectiveness of quetiapine XR (400-800 mg) versus risperidone (2-6 mg) on subjective well-being in schizophrenia (NCT00600756). Primary objective was to demonstrate non-inferiority of quetiapine XR to risperidone in 6-month responder rate using the Subjective Well-Being under Neuroleptics scale (SWN-K) (per-protocol at Month 6 [PP 6] population). Non-inferiority was defined as the lower limit of the 95% confidence interval (CI) greater than -9.7% for the adjusted difference between quetiapine XR and risperidone. Secondary objectives included non-inferiority of quetiapine XR versus risperidone (lower limit of 95% CI greater than -7.5 points) for SWN-K change from baseline to Month 12 (PP 12). 798 patients were randomised (quetiapine XR, n=395; risperidone, n=403); at Month 12, 212 (54%) and 227 (56%) patients, respectively, completed the study. At Month 6, SWN-K responder rate in the PP 6 population was 65% (136/210) with quetiapine XR and 68% (158/232) with risperidone (adjusted treatment difference: -5.7%; 95% CI: -15.1, 3.7); thus, non-inferiority could not be established. SWN-K change from baseline to Month 12 was 23.2 points for quetiapine XR and 21.1 points for the risperidone group; treatment difference was 2.1 (95% CI: -0.8; 5.0); non-inferiority was established (PP 12). CONCLUSION: SWN-K response at 6 months was comparable between the two antipsychotics. However, with a lower than expected responder rate and a lower than expected number of evaluable patients in the PP 6 population, non-inferiority was not demonstrated. A secondary objective (SWN-K total score) established non-inferiority of quetiapine XR to risperidone at Month 12.

Ca2+ release via ryanodine receptors and Ca2+ entry: major mechanisms in NAADP-mediated Ca2+ signaling in T-lymphocytes.

Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca2+ mobilizing nucleotide essentially involved in T cell activation. Using combined microinjection and single cell calcium imaging, we demonstrate that co-injection of NAADP and the D-myo-inositol 1,4,5-trisphosphate antagonist heparin did not inhibit Ca2+ mobilization. In contrast, co-injection of the ryanodine receptor antagonist ruthenium red efficiently blocked NAADP induced Ca2+ signalling. This pharmacological approach was confirmed using T cell clones stably transfected with plasmids expressing antisense mRNA targeted specifically against ryanodine receptors. NAADP induced Ca2+ signaling was strongly reduced in these clones. In addition, inhibition of Ca2+ entry by SK&F 96365 resulted in a dramatically decreased Ca2+ signal upon NAADP injection. Gd3+, a known blocker of Ca2+ release activated Ca2+ entry, only partially inhibited NAADP mediated Ca2+ signaling. These data indicate that in T cells (i) ryanodine receptor are the major intracellular Ca2+ release channels involved in NAADP induced Ca2+ signals, and that (ii) such Ca2+ release events are largely amplified by Ca2+ entry.

Amplification and propagation of pacemaker Ca2+ signals by cyclic ADP-ribose and the type 3 ryanodine receptor in T cells.

Ligation of the T-cell receptor/CD3 complex results in global Ca(2+) signals that are essential for T-cell activation. We have recently reported that these global Ca(2+) signals are preceded by localized pacemaker Ca(2+) signals. Here, we demonstrate for the first time for human T cells that an increase in signal frequency of subcellular pacemaker Ca(2+) signals at sites close to the plasma membrane, in the cytosol and in the nucleus depends on the type 3 ryanodine receptor (RyR) and its modulation by cyclic ADP-ribose. The spatial distribution of D-myo-inositol 1,4,5-trisphosphate receptors and RyRs indicates a concerted action of both of these receptors/Ca(2+) channels in the generation of initial pacemaker signals localized close to the plasma membrane. Inhibition or knockdown of RyRs resulted in significant decreases in (1) the frequency of initial pacemaker signals localized close to the plasma membrane, and (2) the frequency of localized pacemaker Ca(2+) signals in the inner cytosol. Moreover, upon microinjection of cyclic ADP-ribose or upon extracellular addition of its novel membrane-permeant mimic N-1-ethoxymethyl-substituted cyclic inosine diphosphoribose, similarly decreased Ca(2+) signals were observed in both type 3 RyR-knockdown cells and in control cells microinjected with the RyR antagonist Ruthenium Red. Taken together, our results show that, under physiological conditions in human T cells, RyRs play crucial roles in the local amplification and the spatiotemporal development of subcellular Ca(2+) pacemaker signals.

Knock-down of the type 3 ryanodine receptor impairs sustained Ca2+ signaling via the T cell receptor/CD3 complex.

In Jurkat T cells, the type 3 ryanodine receptor (RyR) was knocked-down by stable integration of plasmid expressing type 3 ryanodine receptor antisense RNA. Stable integration of the antisense plasmid in individual clones was demonstrated by PCR of genomic DNA, expression of antisense RNA by reverse transcriptase PCR, and efficiently reduced expression of type 3 ryanodine receptor protein by Western blot. Selected clones were successfully used to analyze T cell receptor/CD3 complex-mediated Ca(2+) signaling. Reduced expression of the type 3 RyR resulted in (i) significantly decreased Ca(2+) signaling in the sustained phase and (ii) in permeabilized cells in a significantly impaired response toward cyclic ADP-ribose but not to d-myo-inositol 1,4,5-trisphosphate. For the first time, the role of the type 3 RyR in sustained Ca(2+) signaling was directly visualized by confocal Ca(2+) imaging as a significant contribution to the number and the magnitude of subcellular Ca(2+) signals. These data suggest that the type 3 ryanodine receptor is essential in the sustained Ca(2+) response in T cells.