Biomedical subjects

Elke Brylla

Publications and source records attributed to Elke Brylla.

5 recordsLinked to original sources

PubMed2005

Coexpression of preprotachykinin A and B transcripts in the bovine corpus luteum and evidence for functional neurokinin receptor activity in luteal endothelial cells and ovarian macrophages.

Nonneuronal cell sources of tachykinins, such as substance P (SP) and neurokinin B (NKB), have been demonstrated in leukocytes, endothelial cells and endocrine cells, and may play a role in corpus luteum (CL) development. For this reason, we analyzed mRNA presence for the two tachykinin precursors together with the neurokinin-1 receptor and the neurokinin-3 receptor (NK-1R and NK-3R, preferred by SP and NKB, respectively) in bovine CL at various stages in the luteal phase. Using the RT-PCR technique, we detected coexpression for the preprotachykinin A gene (PPT-A), which encodes SP and neurokinin A (NKA), and the preprotachykinin B gene (PPT-B) for NKB in the CL at the development, secretion and regression stages. Coexpression was also noted for NK-1R and NK-3R gene transcripts. Cultures of endothelial cells (ECs) derived from bovine CL expressed NK-1R and NK-3R mRNA, as did ovarian macrophages. Agonist treatment induced a stronger intracellular calcium ([Ca2+]i) increase after activation of NK-1R compared to NK-3R, a result that we verified by calcium imaging. This is the first evidence for functional tachykinin receptor activity in luteal ECs and ovarian macrophages from bovine CL.

Animals↗

PubMed2004

Transcripts of neurokinin B and neurokinin 3 receptor in superovulated rat ovaries and increased number of corpora lutea as a non-specific effect of intraperitoneal agonist application.

Neurokinin B (NKB), a member of the tachykinin family, and its neurokinin 3 receptor (NK3-R) are preferentially found in the central nervous system. Others have recently reported on mRNA from this ligand-receptor system in the uterus and on NK3-R expression increasing with age. NKB and NK3-R mRNAs have also been noted in cumulus cells and oocytes from superovulated rats. Intact ovaries before and after puberty have not been studied. In this study, we stimulated 29-day-old rats by s.c. injections with gonadotropins for estrous cycle synchronization in order to elucidate the NKB-NK3-R system's expression and function in the ovary. Simultaneously, NaCl, the NK3-R agonist (Pro(7))-NKB, the antagonist SB 218795, or thiorphan, a neutral endopeptidase inhibitor of tachykinin degradation, were injected intraperitoneally (i.p.) for 3 1/2 consecutive days. First, we demonstrated NKB and NK3-R transcripts in one rat ovary by RT-PCR. No significant mRNA differences were noted between immature ovaries and superovulated ovaries in any of the i.p. applications. Second, the possible role of NK3-R on the ovulatory process was verified by counting corpora lutea (CL) and CL cysts in serial sections of the other ovary derived from the four different groups and embedded in paraffin wax. CL and CL cysts were noted in greater numbers in the pharmacologically treated groups than in the saline-treated group. To validate possible drug effects on the peritoneum, we additionally studied pieces of the omentum majus and retroperitoneal fat tissue. Both tissues were heavily infiltrated by granulocytes similar to a non-specific inflammatory response. The saline-treated group as well as the pharmacologically treated groups appeared to develop this unexpected side effect to a similar degree. We conclude that transcripts of NKB and NK3-R are present before and after puberty in the rat ovary and appear to be expressed at similar levels which may indicate a role for the NKB-NK3-R system in follicle growth. The effect of increased CL formation after application of the NK3-R agonist i.p. is related to a non-specific response.

Animals↗

PubMed2003

Differences between retinal and choroidal microvascular endothelial cells (MVECs) under normal and hypoxic conditions.

The morphological and functional differences between the retinal and choroidal vascular bed raise the question of whether the smallest functional unit, the microvascular endothelial cell (MVEC), also differs in its basal characteristics. Here, we examined bovine retinal and choroidal MVECs (rMVECs, cMVECs) for the presence and regulation of angiogenic mediators and their receptors, and cytokines at the mRNA level using quantitative RT-PCR and differential display. Vascular endothelial growth factor (VEGF) mRNA was expressed in both rMVECs and cMVECs. The basal and hypoxia-increased VEGF mRNA levels were significantly higher in cMVECs, which may indicate a higher capacity for autocrine stimulation in these cells. The mRNA for two VEGF receptors, Flt-1 and Flk-1, was present in rMVECs and cMVECs. Interestingly, rMVECs expressed higher Flt-1 but lower Flk-1 mRNA levels compared to cMVECs. Examining the angiopoietin (Ang)/Tie-2 system, we only detected Ang-1 mRNA at very low levels. While Ang-2 mRNA levels were high in both rMVECs and cMVECs, rMVECs expressed 2-3 times the basal and hypoxia-upregulated Ang-2 mRNA levels than did cMVECs. No difference was found in basal Tie-2 mRNA levels. rMVECs are the more potent producers of macrophage colony-stimulating factor (M-CSF) and granulocyte-macrophage CSF (GM-CSF), whereas cMVECs expressed higher RANTES mRNA levels. In our second approach - screening rMVECs and cMVECs for differentially expressed genes - we found liprin-beta1, calnexin, and sushi-repeat-containing protein, x chromosome (SRPX) mRNA in both MVEC types at varying levels. In summary, MVECs from the retinal and choroidal vascular beds showed quantitative differences in angiogenic regulator expression and in their capability to produce cytokines.

Animals↗

PubMed2003

The intramural innervation of the rabbit upper urinary tract.

The role of the autonomic innervation of the upper urinary tract for pyeloureteral motility is not completely understood. It is still debatable if the autonomic nervous system might play a modulating role on the ureteral peristalsis. The aim of this study was to investigate the distribution and regional variation of the intramural innervation using whole-mount preparations of the rabbit upper urinary tract. Whole-mount preparation was performed at upper urinary tracts of healthy rabbits. Immunohistochemistry was employed using Neurofilament (NF), Tyrosine Hydroxylase (TH), Choline Acetyltransferase (ChAT) and Substance P (SP) antibodies. NADPH-diaphorase and Acetylcholinesterase (AChE) histochemistry was carried out at the specimens. The stains were evaluated using brightfield, fluorescence and laser confocal microscopy. NF-, TH-, ChAT- and SP-immunoreactive (-IR) nerves formed distinct neuronal plexuses at the submucosal and muscle layers. Perivascular TH-, ChAT- and SP-IR fibres were demonstrated. AChE positive nerves were revealed in all layers, but only moderate NADPH-diaphorase positive innervation was found. Renal pelvis, upper and lower ureter showed enriched intrinsic innervation. Ganglia were found at the ureteropelvic border and the distal ureter. Whole-mount preparation technique revealed detailed informations about morphology and regional variation of the intramural innervation of the rabbit upper urinary tract.

Acetylcholinesterase↗

PubMedDate not supplied

Identification of inwardly rectifying potassium channels in bovine retinal and choroidal endothelial cells.

Ion channels were studied using the whole-cell patch clamp technique in bovine retinal and choroidal microvascular endothelial cells (MVEC) cultured under the same conditions. The two types of MVEC expressed inward currents at hyperpolarizing voltage steps and showed small outward currents at depolarizing steps. The extrapolated reversal potentials of the inward currents were near to the potassium equilibrium potential. Cs(+) and the K(+) channel blocker TEA reduced the amplitudes of the currents indicating the selectivity and permeability for potassium. This was confirmed by changes of outside K(+) concentration shifting the I-V curves to the right. RT-PCR studies revealed the presence of mRNA of Kir2.1, an inwardly rectifying K(+) channel, in retinal and choroidal MVEC. The profile of the small outward currents is related to the Kv family but not identical with the Kv1.4 subtype.

Animals↗