Function and expression pattern of TRPM8 in bladder afferent neurons associated with bladder outlet obstruction in rats.

We investigated the function and expression pattern of the transient receptor potential melastatin-8 (TRPM8) in urinary bladder afferent neurons from control and bladder outlet obstruction (BOO) rats. BOO was produced and, after six weeks, the effects of intravesical infusion of menthol, the agonist of TRPM8, were investigated using unanesthetized cystometry. The intravesical infusion of menthol produced an increase in the micturition pressure in both sham surgery and BOO rats. In BOO rats, increased basal and threshold pressure and a decreased micturition interval were observed. Next, the population of TRPM8-positive and the co-expression proportion of TRPM8 with neurochemical markers (NF200 or TRPV1) in the bladder afferent neurons were each compared between the control and BOO rats using retrograde tracing and immunohistochemistry. The population of TRPM8-immunoreactive bladder afferent neurons was larger in BOO rats (3.28±0.43%) than in the control rats (1.33±0.18%). However, there were no statistical differences between the control and BOO rats in the co-expression proportion of neither TRPM8-NF200 (84.1±4.3% vs 79.7±2.7%, p=0.41) nor TRPM8-TRPV1 (33.3±3.6% vs 40.8±2.6%, p=0.08) in the bladder afferent neurons. The present results suggest that the neuronal input through TRPM8-positive bladder afferent neurons are augmented after BOO, however, the neurochemical phenotype of the up-regulated TRPM8-positive bladder afferent neurons is not changed after BOO.

Characteristic morphology and distribution of bone marrow derived cells in the cornea.

Enhanced green fluorescence protein (eGFP)-labeled bone marrow (BM) cells were transplanted into syngeneic C57BL/6 (wild-type) mice to investigate the distribution pattern, immunohistochemical characteristics, three-dimensional structure, and ultrastructure of the BM-derived cells in the mouse cornea using a fluorescence microscope, a confocal laser scanning microscope, and a transmission electron microscope. This study provided direct evidence that two morphologically distinct types of BM-derived cells were distributed in the mouse cornea. The majority of the GFP+ cells showed a flattened polygonal form with obtuse angles and these cells were distributed in the corneal stroma. The other type was the GFP+ cells demonstrating slim cell bodies with long and extremely thin dendrites and which were distributed in the corneal epithelium. The immunohistochemical characteristics and ultrastructure of BM-derived cells suggest that most of these cells have a macrophage lineage, whereas some cells in the corneal stroma do not. Interestingly, the direct intimate contact between GFP-labeled BM derived cells and non-GFP-labeled resident cells within the corneal stroma were also clearly visualized at the fine structural level. These data provide new and more detailed insight into the nature of BM-derived cells in the cornea.