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Operant boxes enable the application of complex behavioural paradigms to support circuit neuroscience and drug discovery research. However, commercial operant box systems are expensive and often not optimised for combining behaviour with neurophysiology. Here we introduce a fully open-source Python-based operant-box system in a 5-choice design (pyOS-5) that enables assessment of multiple cognitive and affective functions. It is optimized for fast turn-over between animals, and for testing of tethered mice for simultaneous physiological recordings or optogenetic manipulation. For reward delivery, we developed peristaltic and syringe pumps based on a stepper motor and 3D-printed parts. Tasks are specified using a Python-based syntax implemented on custom-designed printed circuit boards that are commercially available at low cost. We developed an open-source graphical user interface (GUI) and task definition scripts to conduct assays assessing operant learning, attention, impulsivity, working memory, or cognitive flexibility, alleviating the need for programming skills of the end user. All behavioural events are recorded with millisecond resolution, and TTL-outputs and -inputs allow straightforward integration with physiological recordings and closed-loop manipulations. This combination of features realizes a cost-effective, nose-poke-based operant box system that allows reliable circuit-neuroscience experiments investigating correlates of cognition and emotion in large cohorts of subjects., publishedVersion

Sevelamer hydrochloride (Renagel® ; ), a non-calcium phosphate binder, is capable of reducing progressive coronary artery and aortic calcification. We have recently reported that sevelamer could also prevent and restore bone loss that follows ovariectomy in rats (Vukicevic et al., J Bone Miner Res 2005, S289). In the present study our aim was to determine the biomechanical properties of bones from rats treated with sevelamer. Sprague Dawley rats were ovariectomized (OVX) at 6 months and the sevelamer therapy started immediately in following groups: (1) Sham ; (2) Sham + sevelamer 3% ; (3) OVX ; (4) OVX + sevelamer 1% ; (5) OVX + sevelamer 3% and continued for 25 weeks in the prevention mode. In the restoration mode sevelamer treatment started 3 months after ovariectomy in these groups: (1) Sham ; (2) OVX ; (3) OVX + sevelamer HCl 3% ; (4) OVX + sevelamer calcium carbonate 1%, (5) OVX + sevelamer calcium carbonate 3%, (6) OVX + calcium carbonate 3%. Therapy continued for 12 weeks. In order to evaluate the biomechanical properties of rat bones we used the three-point bending and indentation tests. The intrinsic properties, stress, elastic modulus and toughness were calculated from the maximum load, stiffness, energy absorbed, anterior-posterior diameter, and the moment of inertia. In the restoration mode, rats treated with sevelamer HCl 3% had increased maximum load for 14.75% and stiffness for 12, 85% as compared to OVX animals. The cancellous bone was tested by using the indentation test in the marrow cavity of the distal femoral metaphysis. Sham animals treated with sevelamer 3% increased the maximum load for 26.5%, energy absorbed for 25, 3% and the ultimate strength for 25.9% as compared to sham rats. Sevelamer 3% in OVX rats also increased the maximum load for 69, 2%, stiffness for 70, 1% , energy absorbed for 57% and the ultimate strength for 75% as compared to OVX control animals. In the restoration mode sevelamer hydrochloride 3% had better effect on the biomechanical parameters than other treatment groups. It increased maximum load for 91, 5%, stiffness for 74, 2%, energy absorbed for 91, 4% and the ultimate strength for 89, 5% as compared to OVX animals. These results suggest that sevelamer strongly effects bone strength with a particular reference to the trabecular bone in OVX rats, and could have a positive effect on bone parameters, not only in patients on dialysis, but also in patients with osteoporosis.

Characterization of receptors for osteogenic protein-1/bone morphogenetic protein-7 (OP-1/BMP-7) in rat kidneys. BACKGROUND: Osteogenic protein-1/bone morphogenetic protein-7 (OP-1/BMP-7), a member of the transforming growth factor-beta superfamily, has been shown to prevent kidney damage from ischemia/reperfusion injury in rats. The molecular events involved in OP-1 action on kidney are not yet understood. METHODS: In this study, we evaluated the biodistribution of 125I-labeled OP-1 in rat kidneys. Adult rats received a single intravenous injection of 250 &mgr ; g 125I-labeled OP-1 per kg body wt, a dose that was effective in protecting kidneys from ischemic injury. Tissue localization, in situ hybridization, and immunostaining with a specific receptor antibody were performed to identify OP-1 cellular targets. Also, isolated plasma membranes from kidney cortex and medulla regions were analyzed to identify and characterize receptor structural components that recognize OP-1. RESULTS: At 10 and 180 minutes following injection, the relative uptake of 125I-labeled OP-1 was consistently higher in kidney cortex than in medulla region. Upon autoradiography, kidney tissue sections revealed that OP-1 bound to the convoluted tubule epithelium, glomeruli, and collecting ducts. Moreover, in situ hybridization and immunostaining methods have shown localization of mRNA transcripts and the protein for BMP receptor type II in the cortex and medulla in similar areas as 125I-labeled OP-1. Bulk membranes (enriched with plasma membranes) isolated from the cortex and medulla regions of kidney each bound specifically to 125I-OP-1, and the binding of 125I-labeled OP-1 was inhibited by unlabeled OP-1 in a dose-dependent manner. However, platelet-derived growth factor, transforming growth factor-beta, insulin-like growth factor, fibroblast growth factors, and other members of BMP family such as BMP-2 and cartilage-derived morphogenetic protein-1/growth and differentiation factor-5 (CDMP-1/GDF-5) failed to inhibit the binding of 125I-labeled OP-1 to receptors, suggesting a high degree of specificity with which OP-1 bound to kidney receptors. Scatchard analysis of quantitative binding data indicated that the OP-1 receptors of kidney contained a single class of high-affinity binding sites for OP-1 with an association constant (Ka) of 2.26 x 109 mol/L-1 and a binding capacity of 1.01 pmol of OP-1 per mg membrane protein. When analyzed by a ligand blot technique, plasma membranes isolated from kidney cortex and medulla each showed the presence of a prominent specific band with a relative molecular mass (Mr) of 100 kD. Further analysis by Western blotting indicated that an antibody raised against BMP type II receptor effectively recognized the 100 kD OP-1 binding component of kidney plasma membranes. CONCLUSIONS: We demonstrated, to our knowledge for the first time, the presence of membrane-bound, specific, high-affinity OP-1 receptors in rat kidney tissues, which are likely to mediate OP-1 actions in the kidney. The major OP-1-binding component of the kidney appears to be a long form of BMP type II receptor with a Mr of 100 kD. In vivo and in vitro evidence suggests that the cellular targets for OP-1 are convoluted tubule epithelium, glomeruli, and collecting ducts. OP-1 does not share receptor binding properties with other growth factors, including BMP-2 and CDMP-1, suggesting that its mode of action in kidney appears to be specific.