Expression of anti-Mullerian hormone receptor on the appendix testis in connection with urological disorders.

The female internal sex organs develop from the paramesonephric (Mullerian) duct. In male embryos, the regression of the Mullerian duct is caused by the anti-Mullerian hormone (AMH), which plays an important role in the process of testicular descent. The physiological remnant of the Mullerian duct in males is the appendix testis (AT). In our previous study, we presented evidence for the decreased incidence of AT in cryptorchidism with intraoperative surgery. In this report, the expression of the anti-Mullerian hormone receptor type 2 (AMHR2), the specific receptor of AMH, on the AT was investigated in connection with different urological disorders, such as hernia inguinalis, torsion of AT, cysta epididymis, varicocele, hydrocele testis and various forms of undescended testis. The correlation between the age of the patients and the expression of the AMHR2 was also examined. Reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemistry were used to detect the receptor's mRNA and protein levels, respectively. We demonstrate that AMHR2 is expressed in the ATs. Additionally, the presence of this receptor was proven at the mRNA and protein levels. The expression pattern of the receptor correlated with neither the examined urological disorders nor the age of the patients; therefore, the function of the AT remains obscure.

Inhibition of TASK-3 (KCNK9) channel biosynthesis changes cell morphology and decreases both DNA content and mitochondrial function of melanoma cells maintained in cell culture.

TASK-3 channel overexpression was shown to facilitate the survival of malignantly transformed cells, possibly by providing greater hypoxia tolerance through a still unknown mechanism. Although it has been suggested previously that TASK-3 channels are expressed in the mitochondrial membranes, their role here remains elusive. In this study, a transient transfection of TASK-3 knockdown melanoma cell cultures was produced to show the significance of TASK-3 expression. Reduction of the TASK-3 protein biosynthesis induced characteristic changes in cell morphology, reduced the amount of DNA and decreased metabolic activity and mitochondrial function of melanoma cells when compared with control. These findings indicate that TASK-3 channel expression and function is indispensable for the proliferation and/or survival of the melanoma cells, as they seem to contribute to their mitochondrial functions. The significance is that, in this study, we have shown that TASK-3 channels are expressed in the mitochondria of melanoma malignum cells, and they are essential for maintaining cellular integrity and viability. The TASK-3 knockdown melanoma cell line had altered morphology, reduced DNA content, decreased metabolic activity and impaired mitochondrial function. These data indicate that TASK-3 channels are functionally present in the mitochondria of the melanoma cells, and their function is essential for the survival of these cells, thus TASK-3 channels may be the possible targets of future anticancer therapy.

Cytoplasmic Ca2+ concentration changes evoked by muscarinic cholinergic stimulation in primary and metastatic melanoma cell lines.

Experiments were performed to explore differences between cultured primary and metastatic melanoma cell lines in their muscarinic acetylcholine receptor-mediated intracellular Ca signalization. The expression of type 1 and type 3 muscarinic receptors was detected and compared at the protein level using both immunocytochemistry and semiquantitative western blotting. The functionality of muscarinic receptors was tested by applying carbamylcholine (CCh; 1 mmol/l) and by recording the associated increases in cytoplasmic Ca using Ca imaging with the application of the Ca indicator dye, fluo-4. These data indicate that the expression levels of the receptor proteins were not significantly different in the metastatic (HT199, HT168-M1) and the primary (WM35) cell lines. Although Ca transients were evoked in all the three cell lines by CCh, the proportion of the CCh-positive cells was smaller amongst the WM35 cells. The Ca transients could be effectively blocked by atropine (0.1 mmol/l). The time courses of the Ca transients were highly variable, and in some instances they showed a late (plateau-like) component whose presence crucially depended on the influx of extracellular Ca. When the extracellular Ca concentration was reduced, the duration of the CCh-evoked transients was considerably decreased; a phenomenon that was more pronounced in the metastatic cell lines. Although there are no fundamental differences in the muscarinic receptor-mediated Ca signalization of the primary and metastatic cell lines, the quantitative differences showed in this study may partially explain the increased malignancy and migratory potential of the metastatic cells.

Voltage-gated potassium channel (Kv) subunits expressed in the rat cochlear nucleus.

Because the neuronal membrane properties and firing characteristics are crucially affected by the depolarization-activated K(+) channel (Kv) subunits, data about the Kv distribution may provide useful information regarding the functionality of the neurons situated in the cochlear nucleus (CN). Using immunohistochemistry in free-floating slices, the distribution of seven Kv subunits was described in the rat CN. Positive labeling was observed for Kv1.1, 1.2, 1.6, 3.1, 3.4, 4.2, and 4.3 subunits. Giant and octopus neurons showed particularly strong immunopositivity for Kv3.1; octopus neurons showed intense Kv1.1- and 1.2-specific reactions also. In the latter case, an age-dependent change of the expression pattern was also documented; although both young and older animals produced definite labeling for Kv1.2, the intensity of the reaction increased in older animals and was accompanied with the translocation of the Kv1.2 subunits to the cell surface membrane. The granule cell layer exhibited strong Kv4.2-specific immunopositivity, and markedly Kv4.2-positive glomerular synapses were also seen. It was found that neither giant nor pyramidal cells were uniform in terms of their Kv expression patterns. Our data provide new information about the Kv expression of the CN and also suggest potential functional heterogeneity of the giant and pyramidal cells.

Mitochondrial expression of the two-pore domain TASK-3 channels in malignantly transformed and non-malignant human cells.

The presence of TASK-3 channels has been described in a number of healthy and malignantly transformed cells, showing mainly intracellular distribution with relatively insignificant labelling of the cell surface membrane. In this work, immunochemical and molecular biology methods were utilised to establish the intracellular organelle whose TASK-3 expression accounts for this strong intracellular labelling using cultured melanoma and HaCaT cells. Before the immunocytochemical experiments, the presence of TASK-3 mRNA was also confirmed in melanoma cells. Comparison of the results of the TASK-3- and mitochondrion-specific labelling indicated that the TASK-3 channel subunits were strongly expressed by mitochondria in both investigated cell types. Moreover, prominent TASK-3 expression of keratinocytes could also be demonstrated in histological sections excised from the human skin. These results indicate that TASK-3 channels are present in the mitochondria in both malignantly transformed and healthy cells, suggesting that they might have roles in ensuring mitochondrial functions.

Rhodamine backfilling and confocal microscopy as a tool for the unambiguous identification of neuronal cell types: a study of the neurones of the rat cochlear nucleus.

Adequate interpretation of the functional data characterising the projection neurones of the cochlear nucleus (CN) is impossible without the unequivocal classification of these cell types at the end of the experiments. In this study, morphological criteria applicable for unambiguous identification of CN neurones have been sought. The neurones were labelled with rhodamine from incisions severing the projection pathways of the individual cell types, allowing their selective labelling and morphological characterisation. Confocal microscopy was employed for the investigation of the rhodamine-filled cells whose morphology was assessed after reconstructing the three-dimensional images of the cell bodies and proximal processes. The diameters of the somata and the number of processes originating from the cell bodies were also determined. In most of the cases, unambiguous identification of the bushy, octopus and Purkinje-like cells was relatively straightforward. On the other hand, precise classification of the pyramidal cells was often difficult, especially because giant cells could easily possess morphological features resembling pyramidal neurones. Occasionally, giant cells also mimicked the appearance of octopus neurones, which may be another important source of identification error, especially as these two cell types are often situated close to each other in the CN. It is concluded that morphological criteria defined in the present work may be effectively applied for the unambiguous identification of the projection neurones of the CN, even following functional measurements, when the correct cell classification is essential for the interpretation of the experimental data. Moreover, the present study also confirmed that Purkinje-like cells project to the cerebellum.