| 1. |
- Chen, Hui, et al.
(författare)
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Repeat periods of electrical stimulation prolong the modulation of the micturition reflex in the rat
- 2018
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Ingår i: Neurourology and Urodynamics. - : WILEY. - 0733-2467 .- 1520-6777. ; 37:8, s. 2480-2486
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Tidskriftsartikel (refereegranskat)abstract
- AimsMethodsThe aim of this study was to determine if the duration of the micturition reflex modulation could be prolonged by repeated periods of afferent stimulation in the decorticated rat. Eighteen female Sprague-Dawley rats were used for the study, 10 for intravesical electrical stimulation (IVES), and 8 for Ano-genital pudendal afferents stimulation. Repeated constant flow cystometries were performed with body-warm saline (0.06-0.1mL/min) at about 10min interval. The selected afferents were stimulated continuously for 5min at maximal intensity. The same stimulation was repeated six times with a pause of 5min between the stimulations. The mean threshold volume of cystometries performed during one hour before and each hour after the stimulation were compared. ResultsConclusionsAfter six periods of IVES, the micturition threshold volume decreased to its lowest value (62% of control) during the first hour and remained at 80% 4h later (n=10, Pamp;lt;0.01). Ano-genital afferent stimulation produced a corresponding increase in the micturition threshold volume. The long-lasting poststimulation effect was again observed for more than 5h. During the first hour the mean threshold volume increased to 211% of controls and it remained at about this level for the entire observation period (n=8, Pamp;lt;0.01). Repeated short periods of stimulation prolonged the modulatory effect well beyond the stimulation period. The findings provide experimental evidence supporting the clinical application of IVES and ano-genital stimulation for treatment of neurogenic urinary bladder dysfunction.
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| 2. |
- Jarvis, Erich D., et al.
(författare)
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Whole-genome analyses resolve early branches in the tree of life of modern birds
- 2014
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 346:6215, s. 1320-1331
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Tidskriftsartikel (refereegranskat)abstract
- To better determine the history of modern birds, we performed a genome-scale phylogenetic analysis of 48 species representing all orders of Neoaves using phylogenomic methods created to handle genome-scale data. We recovered a highly resolved tree that confirms previously controversial sister or close relationships. We identified the first divergence in Neoaves, two groups we named Passerea and Columbea, representing independent lineages of diverse and convergently evolved land and water bird species. Among Passerea, we infer the common ancestor of core landbirds to have been an apex predator and confirm independent gains of vocal learning. Among Columbea, we identify pigeons and flamingoes as belonging to sister clades. Even with whole genomes, some of the earliest branches in Neoaves proved challenging to resolve, which was best explained by massive protein-coding sequence convergence and high levels of incomplete lineage sorting that occurred during a rapid radiation after the Cretaceous-Paleogene mass extinction event about 66 million years ago.
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| 3. |
- Mai, Junyan, et al.
(författare)
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Prolonged Inhibitory Effects of Repeated Tibial Nerve Stimulation on the Micturition Reflex in Decorticated Rats
- 2022
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Ingår i: Neuromodulation. - : ELSEVIER. - 1094-7159 .- 1525-1403. ; 25:8, s. 1115-1121
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Tidskriftsartikel (refereegranskat)abstract
- Objective: This study aimed to determine whether a short-term repeated stimulation of tibial nerve afferents induces a prolonged modulation effect on the micturition reflex in a decorticated rat model. Material and Methods: Fifteen female Sprague-Dawley rats (250-350 g) were fully decorticated and paralyzed in the study. Tibial nerve stimulation (TNS) was delivered by inserting two pairs of needle electrodes close to the nerves at the level of the medial malleolus. Constant flow cystometries (0.07 mL/min) at approximately ten-minute intervals were performed, and the micturition threshold volume (MTV) was recorded and used as a dependent variable. After four to five stable recordings, the tibial nerves of both sides were stimulated continuously for five minutes at 10 Hz and at an intensity of three times the threshold for alpha-motor axons. Six same stimulations were applied repeatedly, with an interval of five minutes between each stimulation. Mean MTV was calculated on the basis of several cystometries in each half-hour period before, during, and after the six repeated TNS. Results: During the experiment, all the animals survived in good condition with relatively stable micturition reflexes, and a significant increase in MTV was detected after TNS. The strongest effect (mean = 178%) was observed during the first 30 minutes after six repeated stimulations. This obvious threshold increase remained for at least five hours. Conclusions: A prolonged poststimulation modulatory effect on the micturition reflex was induced by short-term repeated TNS in decorticated rats. This study provides a theoretical explanation for the clinical benefit of TNS in patients with overactive bladder and suggests decorticated rats as a promising model for further investigation of the neurophysiological mechanisms underlying the bladder inhibitory response induced by TNS.
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| 4. |
- Zeng, Jianwen, et al.
(författare)
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Bladder mechanoreceptor changes after artificial bladder outlet obstruction in the anesthetized rat
- 2012
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Ingår i: Neurourology and Urodynamics. - : Wiley-Blackwell. - 0733-2467 .- 1520-6777. ; 31:1, s. 178-184
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Tidskriftsartikel (refereegranskat)abstract
- Aims Experimental animal models of bladder outlet obstruction (BOO) have reproduced several features of BOO in man, i.e., detrusor hypertrophy, instability, frequency, and residual urine. This study was focused on the mechanisms underlying the development of residual urine in patient with benign prostatic hyperplasia (BPH) by examining changes in tension sensitivity of bladder mechanoreceptors in rat model. Methods: Female adult Sprague-Dawley rats including 12 BOO and 17 sham operated rats were used in this study. Cystometrograms together with the bladder afferent activity were recorded. Tension sensitivity of the afferents was determined by plotting the normalized afferent response against the contraction evoked bladder pressure at different volumes. Degree of obstruction was assessed by the wet weight of the bladder at the end of the experiment. Results: The bladder weight, maximal bladder capacity, micturition threshold volume, peak contraction force, and volume at peak contraction force were all significantly increased in obstructed animals. The threshold volume for afferent activation was increased ( mean 0.60 ml compared to 0.15 ml in controls; P andlt; 0.001), positively correlated with the bladder weight ( r 0.74). The tension sensitivity of the bladder mechanoreceptors and the slope of their normalized pressure-response functions were significantly lower at the comparable volumes in the obstructed animals. Conclusions: Rats with BOO had bladder mechanoreceptors with higher threshold volumes and lower tension sensitivity. Such changes would result in a weaker afferent drive of the micturition reflex. Similar changes may contribute to the development of residual urine and retention in patients with BOO. Neurourol. Urodynam. 31: 178-184, 2012. (C) 2011 Wiley Periodicals, Inc.
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| 5. |
- Zeng, Jianwen, et al.
(författare)
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Cause of Residual Urine in Bladder Outlet Obstruction: An Experimental Study in the Rat
- 2012
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Ingår i: Journal of Urology. - : Elsevier. - 0022-5347 .- 1527-3792. ; 188:3, s. 1027-1032
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: We explored the role of bladder mechanoreceptors in post-void residual urine in rats with bladder outlet obstruction. less thanbrgreater than less thanbrgreater thanMaterials and Methods: Partial bladder outlet obstruction was induced by a urethral ligature in 11 adult female Sprague-Dawley (R) rats. Nine sham operated rats served as controls. The outcome was evaluated in acute experiments using alpha-chloralose anesthesia 6 weeks later. Bladders were catheterized for infusion, pressure recording and intravesical electrical stimulation. Bladder efferent activity was recorded from a thin pelvic nerve branch close to the bladder. Micturition contractions were triggered at different bladder volumes by a brief train of electrical stimulation of bladder afferents while monitoring post-stimulus efferent activity and reflex bladder contractions. The degree of obstruction was assessed by bladder wet weight at the end of the experiment. less thanbrgreater than less thanbrgreater thanResults: Bladder weight, micturition threshold volume, anatomical bladder capacity and peak contraction force were significantly increased in obstructed rats. In sham operated controls a triggered micturition reflex was sustained by afferent feedback from the bladder until the bladder was empty. In contrast, reflex discharges failed with substantial volume remaining in the bladder in obstructed rats. The minimal micturition reflex volume correlated positively with bladder weight, micturition threshold volume and maximal bladder capacity (r andgt;= 0.74). less thanbrgreater than less thanbrgreater thanConclusions: In rats with partial bladder outlet obstruction the micturition reflex failed before the bladder was empty due to a decreased afferent drive from bladder mechanoreceptors. Similar changes may contribute to post-void residual urine in humans with bladder outlet obstruction.
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| 6. |
- Zeng, Jianwen, et al.
(författare)
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Non-uniform changes in membrane receptors in the rat urinary bladder following outlet obstruction.
- 2015
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 762, s. 82-88
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the present study was to investigate the expression and distribution of membrane receptors after bladder outlet obstruction (BOO). Partial bladder outlet obstruction (BOO) was induced in female rats and bladders were harvested after either 10 days or 6 weeks of BOO. The expression of different receptors was surveyed by microarrays and corroborated by immunohistochemistry and western blotting. A microarray experiment identified 10 membrane receptors that were differentially expressed compared to sham-operated rats including both upregulated and downregulated receptors. Four of these were selected for functional experiments on the basis of magnitude of change and relevance to bladder physiology. At 6 weeks of BOO, maximal contraction was reduced for neuromedin B and vasopressin (AVP), consistent with reductions of receptor mRNA levels. Glycine receptor-induced contraction on the other hand was increased and receptor mRNA expression was accordingly upregulated. Maximal relaxation by the β3-adrenergic receptor agonist CL316243 was reduced as was the receptor mRNA level. Immunohistochemistry supported reduced expression of neuromedin B receptors, V1a receptors and β3-adrenergic receptors, but glycine receptor expression appeared unchanged. Western blotting confirmed repression of V1a receptors and induction of glycine receptors in BOO. mRNA for vasopressin was detectable in the bladder, suggesting local AVP production. We conclude that changes in receptor expression following bladder outlet obstruction are non-uniform. Some receptors are upregulated, conferring increased responsiveness to agonist, whereas others are downregulated, leading to decreased agonist-induced responses. This study might help to select pharmacological agents that are effective in modulating lower urinary tract symptoms in BOO.
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| 7. |
- Zeng, Jianwen, et al.
(författare)
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Vasopressin-induced mouse urethral contraction is modulated by caveolin-1.
- 2015
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Ingår i: European Journal of Pharmacology. - : Elsevier BV. - 1879-0712 .- 0014-2999. ; 750, s. 59-65
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Tidskriftsartikel (refereegranskat)abstract
- Caveolae are 50-100nm large invaginations in the cell membrane that are considered to play roles in receptor signaling. Here we aimed to investigate the expression and distribution of the arginine-vasopressin (AVP) V1a receptor and its functional dependence on caveolin-1 (Cav1) in the mouse urethra. Female Cav1 knockout (KO) and wild type (WT) mice were used, and urethral preparations were micro-dissected for mechanical experiments. Methyl-β-cyclodextrin (mβcd) was used to deplete cholesterol and to disrupt caveolae. Protein expression and localization was determined using immunofluorescence and western blotting and transcript expression was determined by qRT-PCR. We found that Cav1 and AVP V1a receptors were expressed in urethral smooth muscle cells with apparent co-localization at the cell membrane. AVP caused urethral contraction that was inhibited by the V1a receptor antagonist SR49059. Concentration-response curves for AVP were right-shifted and maximal contraction was reduced in Cav1 KO mice and after mβcd treatment. In addition to caveolin-1 we also detected caveolin-2, cavin-1 and cavin-3 in the mouse urethra by western blotting. Caveolin-2, cavin-1 and cavin-3 as well as V1a receptor expression was reduced in KO urethra. We conclude that AVP regulates urethral contractility via the V1a receptor through a Cav1-dependent mechanism involving, in part, altered V1a receptor expression.
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| 8. |
- Zhu, Baoyi, et al.
(författare)
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Similar regulatory mechanisms of caveolins and cavins by myocardin family coactivators in arterial and bladder smooth muscle
- 2017
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Ingår i: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 12:5
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Tidskriftsartikel (refereegranskat)abstract
- Caveolae are membrane invaginations present at high densities in muscle and fat. Recent work has demonstrated that myocardin family coactivators (MYOCD, MKL1), which are important for contractile differentiation and cell motility, increase caveolin (CAV1, CAV2, CAV3) and cavin (CAVIN1, CAVIN2, CAVIN3) transcription, but several aspects of this control mechanism remain to be investigated. Here, using promoter reporter assays we found that both MKL1/MRTF-A and MKL2/MRTF-B control caveolins and cavins via their proximal promoter sequences. Silencing of MKL1 and MKL2 in smooth muscle cells moreover reduced CAV1 and CAVIN1 mRNA levels by well over 50%, as did treatment with second generation inhibitors of MKL activity. GATA6, which modulates expression of smooth muscle-specific genes, reduced CAV1 and CAV2, whereas the cavins were unaffected or increased. Viral overexpression of MKL1 and myocardin induced caveolin and cavin expression in bladder smooth muscle cells from rats and humans and MYOCD correlated tightly with CAV1 and CAVIN1 in human bladder specimens. A recently described activator of MKL-driven transcription (ISX) failed to induce CAV1/CAVIN1 which may be due to an unusual transactivation mechanism. In all, these findings further support the view that myocardin family coactivators are important transcriptional drivers of caveolins and cavins in smooth muscle.
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