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Background: A role for the transient receptor potential (TRP) A1 ion channel in rat lower urinary tract (LUT) sensation and disease has been proposed, but in the human LUT no information on TRPA1 activity is available. Objectives: To investigate the distribution of TRPA1 in the human urethra and to study the effect of TRPA1 agonists on isolated urethral strip preparations. Design, settings, and participants: Urethral specimens were obtained preoperatively from 10 patients and were freshly prepared for Western blot, immunohistochemistry, and functional in vitro investigations. Measurements: The expression patterns of TRPA1 were studied with Western blot and immunohistochemistry. The effects of allyl isothiocyanate (A1), cinnamaldehyde (CA), and NaHS (donor of H2S) on tension of urethral strips were investigated in tissue baths. Results and limitations: TRPA1 immunoreactivity (-IR) was found in nerve fibres in the suburothelial space and was also located to nerve fibres of the muscle layer. Single TRPA1-IR nerves extended into the urothelium. A majority, but not all TRPA1-IR nerves also expressed immunoreactivity for CGRP or TRPV1. In the urothelium, TRPV1 was located to the outer layers whereas TRPA1 was observed in basal urothelial cells. Interspersed between strands of smooth muscle cells of the urethral wall, TRPA1- and vimentin-IR cells containing central nuclei and slender cytoplasmatic extensions were observed. In functional experiments, TRPA1-agonists had no contractile effect in urethral preparations. After precontraction with phenylephrine, AI, CA, and NaHS caused concentration-dependent relaxations of urethral strip preparations.´ Conclusions: The localization of TRPA1 to nerves that also express TRPV1 and CGRP, and in urothelial cells and interstitial cells, as well as the findings that TRPA1 agonists can modify tone of urethral preparations, propose a role for TRPA1 in afferent and efferent sensory signaling of the human outflow region.

Die Regulation der zytosolischen Kalziumkonzentration durch die cGMP-abhängige Proteinkinase I (cGKI) spielt bei der Relaxierung der glatten Muskulatur eine bedeutende Rolle. IRAG, ein Substratprotein der cGKI, wird vor allem in glattmuskulären Geweben exprimiert. In dieser Arbeit konnte mittels Kalziummessungen in COS 7 Zellen und glatten Gefäßmuskelzellen die Beteiligung von IRAG an der Regulation des zytosolischen Kalziumspiegels durch cGMP/cGKI nachgewiesen werden. Zusätzlich wurden mit Hilfe des Cre/loxP Rekombinationssystems chimäre Mäuse generiert, welche die Grundlagen zur Etablierung von Mauslinien mit einem konventionell oder konditional deletierten IRAG Gen darstellen. Diese Mauslinien werden einen wichtigen Beitrag leisten, die physiologische und pathophysiologische Funktion von IRAG weiter zu analysieren., The regulation of the cytosolic calcium concentration by cGMP-dependent protein kinase I (cGKI) plays an outstanding role in relaxation of smooth muscle. IRAG, a substrate protein of cGKI, is predominantly expressed in smooth muscle tissue. Using the Calcium Imaging Technique in COS 7 cells and vascular smooth muscle cells, the involvement of IRAG in the regulation of the cytosolic calcium concentration by cGMP/cGKI could be demonstrated in this work. Additionally chimeric mice were generated by means of the Cre/loxP recombination system, which provide the basis for the establishment of mouse strains with a conventional or conditional deleted IRAG gene. These mouse strains make an important contribution to further analysis of the physiological and pathophysiological function of IRAG.

Die Regulation der zytosolischen Kalziumkonzentration durch die cGMP-abhängige Proteinkinase I (cGKI) spielt bei der Relaxierung der glatten Muskulatur eine bedeutende Rolle. IRAG, ein Substratprotein der cGKI, wird vor allem in glattmuskulären Geweben exprimiert. In dieser Arbeit konnte mittels Kalziummessungen in COS 7 Zellen und glatten Gefäßmuskelzellen die Beteiligung von IRAG an der Regulation des zytosolischen Kalziumspiegels durch cGMP/cGKI nachgewiesen werden. Zusätzlich wurden mit Hilfe des Cre/loxP Rekombinationssystems chimäre Mäuse generiert, welche die Grundlagen zur Etablierung von Mauslinien mit einem konventionell oder konditional deletierten IRAG Gen darstellen. Diese Mauslinien werden einen wichtigen Beitrag leisten, die physiologische und pathophysiologische Funktion von IRAG weiter zu analysieren., The regulation of the cytosolic calcium concentration by cGMP-dependent protein kinase I (cGKI) plays an outstanding role in relaxation of smooth muscle. IRAG, a substrate protein of cGKI, is predominantly expressed in smooth muscle tissue. Using the Calcium Imaging Technique in COS 7 cells and vascular smooth muscle cells, the involvement of IRAG in the regulation of the cytosolic calcium concentration by cGMP/cGKI could be demonstrated in this work. Additionally chimeric mice were generated by means of the Cre/loxP recombination system, which provide the basis for the establishment of mouse strains with a conventional or conditional deleted IRAG gene. These mouse strains make an important contribution to further analysis of the physiological and pathophysiological function of IRAG.