To clarify the lower urinary tract function in mice, we compared bladder and urethral activity between rats and mice with or without spinal cord injury (SCI). Female Sprague-Dawley rats and C57BL/6N mice were divided into five groups:1) spinal intact (SI) rats,2) SI mice,3) pudendal nerve transection (PNT) SI mice,4) spinal cord injury (SCI) rats, and 5) SCI mice. Continuous cystometry (CMG) and external urethral sphincter (EUS)-electromyogram (EMG) analyses were conducted under an awake, restrained condition. During voiding bladder contractions, SI animals exhibited EUS bursting with alternating active and silent periods, which, in rats but not mice, coincided with small-amplitude intravesical pressure oscillations in CMG recordings. In SI mice with bursting-like EUS activity, the duration of active periods was significantly shorter by 46% (32 ± 5 ms) compared with SI rats (59 ± 9 ms). In PNT-SI mice, there were no significant differences in any of cystometric parameters compared with SI mice. In SCI rats, fluid elimination from the urethra and the EUS bursting occurred during small-amplitude intravesical pressure oscillations. However, SCI mice did not exhibit clear EUS bursting activity or intravesical pressure oscillations but rather exhibited intermittent voiding with slow large-amplitude reductions in intravesical pressure, which occurred during periods of reduced EUS activity. These results indicate that EUS pumping activity is essential for generating efficient voiding in rats with or without spinal cord injury. However, EUS bursting activity is not required for efficient voiding in SI mice and does not reemerge in SCI mice in which inefficient voiding occurs during periods of reduced tonic EUS activity.

Stop-signal task (SST) has been a key paradigm for probing human brain mechanisms underlying response inhibition, and the inhibition observed in SST is now considered to largely depend on a fronto basal ganglia network consisting mainly of right inferior frontal cortex, pre-supplementary motor area (pre-SMA), and basal ganglia, including subthalamic nucleus, striatum (STR), and globus pallidus pars interna (GPi). However, causal relationships between these frontal regions and basal ganglia are not fully understood in humans. Here, we partly examined these causal links by measuring human fMRI activity during SST before and after excitatory/inhibitory repetitive transcranial magnetic stimulation (rTMS) of pre-SMA. We first confirmed that the behavioral performance of SST was improved by excitatory rTMS and impaired by inhibitory rTMS. Afterward, we found that these behavioral changes were well predicted by rTMSinduced modulation of brain activity in pre-SMA, STR, and GPi during SST. Moreover, by examining the effects of the rTMS on restingstate functional connectivity between these three regions, we showed that the magnetic stimulation of pre-SMA significantly affected intrinsic connectivity between pre-SMA and STR, and between STR and GPi. Furthermore, the magnitudes of changes in resting-state connectivity were also correlated with the behavioral changes seen in SST. These results suggest a causal relationship between pre-SMA and GPi via STR during response inhibition, and add direct evidence that the fronto basal ganglia network for response inhibition consists of multiple top-down regulation pathways in humans.

We demonstrate here that the transient receptor potential melastatin subfamily channel, TRPM4, controls migration of bone marrow-derived mast cells (BMMCs), triggered by dinitrophenylated human serum albumin (DNP-HSA) or stem cell factor (SCF). Wild-type BMMCs migrate after stimulation with DNP-HSA or SCF whereas both stimuli do not induce migration in BMMCs derived from TRPM4 knockout mice (trpm4(-/-)). Mast cell migration is a Ca(2+)-dependent process, and TRPM4 likely controls this process by setting the intracellular Ca(2+) level upon cell stimulation. Cell migration depends on filamentous actin (F-actin) rearrangement, since pretreatment with cytochalasin B, an inhibitor of F-actin formation, prevented both DNP-HSA- and SCF-induced migration in wild-type BMMC. Immunocytochemical experiments using fluorescence-conjugated phalloidin demonstrate a reduced level of F-actin formation in DNP-HSA-stimulated BMMCs from trpm4(-/-) mice. Thus, our results suggest that TRPM4 is critically involved in migration of BMMCs by regulation of Ca(2+)-dependent actin cytoskeleton rearrangements.

Testicular torsion is a common urological emergency among adolescent boys and young men. Rotation of the testis and twisting of the spermatic cord rapidly leads to ischemia, resulting in a loss of germ cells. Thus, prompt diagnosis and urgent surgical intervention are required, but the subsequent release of the torsion induces reperfusion injury, which causes further damage to the ischemic testis. Testicular torsion -detorsion (ischemia-reperfusion) injury triggers the generation of reactive oxygen species, pro-inflammatory cytokines, neutrophil recruitment, lipid peroxidation, anoxia and apoptosis, which carry a significant risk of subsequent infertility. Previously, the effects of numerous pharmacological agents and treatments have been evaluated to prevent testicular ischemia-reperfusion injury in animal models. We propose a new treatment, especially postconditioning, to prevent adverse effects of ischemiareperfusion injury after testicular torsion-detorsion.

In SCI mice, NGF is involved in the emergence of NVCs in association with increased expression of TRP receptors that are predominantly found in C-fiber afferent pathways. Thus, NGF targeting treatments could be effective for treating storage problems such as detrusor overactivity after SCI.

The posterior parietal cortex (PPC) features close anatomical and functional relationships with the prefrontal cortex. However, the necessity of the PPC in executive functions has been questioned. The present study used the stop-signal task to examine response inhibition, an executive function that inhibits prepotent response tendency. The brain activity and resting-state functional connectivity were measured to analyze a parcellation-based network that was aimed at identifying a candidate PPC region essential for response inhibition in humans. The intraparietal sulcus (IPS) was activated during response inhibition and connected with the inferior frontal cortex and the presupplementary motor area, the two frontal regions known to be necessary for response inhibition. Next, transcranial magnetic stimulation (TMS) was used to test the essential role of the IPS region for response inhibition. TMS over the IPS region prolonged the stop-signal reaction time (SSRT), the standard behavioral index used to evaluate stopping performance, when stimulation was applied 30 -0 ms before stopping. On the contrary, stimulation over the temporoparietal junction region, an area activated during response inhibition but lacking connectivity with the two frontal regions, did not show changes in SSRT. These results indicate that the IPS identified using the parcellation-based network plays an essential role in executive functions.

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We examined bladder and urethral sphincter activity in mice with or without spinal cord injury (SCI) after C-fiber afferent desensitization induced by capsaicin pretreatment and changes in electrophysiological properties of mouse bladder afferent neurons 4 wk after SCI. Female C57BL/6N mice were divided into four groups: ) spinal intact (SI)-control,) SI-capsaicin pretreatment (Cap), ) SCI-control, and) SCI-Cap groups. Continuous cystometry and external urethral sphincter (EUS)-electromyogram (EMG) were conducted under an awake condition. In the Cap groups, capsaicin (25, 50, or 100 mg/kg) was injected subcutaneously 4 days before the experiments. In the SI-Cap group, 100 mg/kg capsaicin pretreatment significantly increased bladder capacity and decreased the silent period duration of EUS/EMG compared with the SI-control group. In the SCI-Cap group, 50 and 100 mg/kg capsaicin pretreatment decreased the number of nonvoiding contractions (NVCs) and the duration of reduced EUS activity during voiding, respectively, compared with the SCI-control group. In SCI mice, hexamethonium, a ganglionic blocker, almost completely blocked NVCs, suggesting that they are of neurogenic origin. Patch-clamp recordings in capsaicin-sensitive bladder afferent neurons from SCI mice showed hyperexcitability, which was evidenced by decreased spike thresholds and increased firing rate compared with SI mice. These results indicate that capsaicin-sensitive C-fiber afferent pathways, which become hyperexcitable after SCI, can modulate bladder and urethral sphincter activity in awake SI and SCI mice. Detrusor overactivity as shown by NVCs in SCI mice is significantly but partially dependent on capsaicin-sensitive C-fiber afferents, whereas the EUS relaxation during voiding is enhanced by capsaicin-sensitive C-fiber bladder afferents in SI and SCI mice.