The US National Institute of Neurological Disorders and Stroke convened major stakeholders in June 2012 to discuss how to improve the methodological reporting of animal studies in grant applications and publications. The main workshop recommendation is that at a minimum studies should report on sample-size estimation, whether and how animals were randomized, whether investigators were blind to the treatment, and the handling of data. We recognize that achieving a meaningful improvement in the quality of reporting will require a concerted effort by investigators, reviewers, funding agencies and journal editors. Requiring better reporting of animal studies will raise awareness of the importance of rigorous study design to accelerate scientific progress.

Inositol-1,4,5-trisphosphate receptor-mediated Ca mobilization is not required for cerebellar long-term depression in reduced preparations. J. Neurophysiol. 80: 2963-2974, 1998. Cerebellar long-term depression (LTD) is a cellular model system of information storage in which coincident parallel fiber and climbing fiber activation of a Purkinje neuron (PN) gives rise to a sustained attenuation of parallel fiber-PN synaptic strength. Climbing fiber and parallel fiber inputs may be replaced by direct depolarization of the PN and exogenous glutamate pulses, respectively. The parallel fiber-PN synapse has a high-density of mGluR1 receptors that are coupled to phosphoinositide turnover. Several lines of evidence indicated that activation of mGluR1 by parallel fiber stimulation is necessary for the induction of cerebellar LTD. Because phosphoinositide hydrolysis has two initial products, 1, 2-diacylglycerol and inositol-1,4,5-trisphosphate (IP3), we wished to determine whether IP3 signaling via IP3 receptors and consequent Ca mobilization were necessary for the induction of cerebellar LTD. First, ratiometric imaging of free cytosolic Ca was performed on both acutely dissociated and cultured PNs. It was determined that the threshold for glutamate pulses to contribute to LTD induction was below the threshold for producing a Ca transient. Furthermore, the Ca transients produced by depolarization alone and glutamate plus depolarization were not significantly different. Second, the potent and selective IP3 receptor channel blocker xestospongin C was not found to affect the induction of LTD in either acutely dissociated or cultured PNs at a concentration that was sufficient to block mGluR1-evoked Ca mobilization. Third, replacement of mGluR activation by exogenous synthetic diacylglycerol in an LTD induction protocol was successful. Taken together, these results suggest that activation of an IP3 signaling cascade is not required for induction of cerebellar LTD in reduced preparations.

1. Zinc-protoporphyrin-IX (ZnPP-IX) is an inhibitor of the enzyme heme-oxygenase-2 (HO-2) and consequently has been used to examine the role of carbon monoxide production in neural tissues. We have measured voltage-gated Ca current in AtT-20 pituitary cells using the whole-cell patch-clamp technique and have assessed the effects of extracellularly applied ZnPP-IX and related compounds. 2. Ca currents evoked by depolarizing steps from a holding potential of -90 mV were of the high-threshold, slowly inactivating type. Fifty-six percent of this current was blocked by 10 microM nifedipine and 16% by 3 microM omega-conotoxin with the remainder resistant to both drugs in combination, suggesting that the total Ca current was a mixture of L, N, and possibly P-type conductances. 3. Bath application of ZnPP-IX resulted in an irreversible, dose-dependent attenuation of Ca current. Five micromolar ZnPP-IX produced a 62% reduction of peak current amplitude with no shift in the current-voltage relation, 0.5 microM produced a 19% reduction, and 0.05 microM produced a variable response, either a small transient attenuation or potentiation. 4. The attenuation of Ca current by 5 microM ZnPP-IX could be nearly completely blocked by co-application of superoxide dismutase in the bath (90 U/ml) but not by addition of an inhibitor of cGMP-dependent protein kinase to the internal saline (KT5823, 1 microM). 5. Other inhibitors of heme-oxygenase with similar potency such as tin-protoporphyrin-IX (Sn-PP-IX) and Zn-deuteroporphyrin-bis-glycol (ZnBG) did not attenuate Ca current when applied at 5microM.(ABSTRACT TRUNCATED AT 400 WORDS)