Exogenous overexpression of nerve growth factor in the urinary bladder produces bladder overactivity and altered micturition circuitry in the lumbosacral spinal cord

<p>Abstract</p> <p>Background</p> <p>Exogenous NGF or saline was delivered to the detrusor smooth muscle of female rats for a two-week period using osmotic mini-pumps. We then determined: (1) bladder function using conscious cystometry; (2) organization of micturition reflexes using Fos protein expression in lumbosacral (L5-S1) spinal cord neurons; (3) calcitonin gene-related peptide (CGRP)-immunoreactivity (IR) in lumbosacral spinal cord segments.</p> <p>Methods</p> <p>An osmotic pump infused 0.9% NaCl (n = 6) or NGF (n = 6)(2.5 μg/μl solution; 0.5 μl/hr) for two weeks into the bladder wall. NGF bladder content was determined by enzyme-linked immunoassays. Bladder function was assessed with conscious cystometry. Immunohistochemical and imaging techniques were used to determine the distribution of Fos-IR cells and CGRP expression in the L5-S1 spinal cord in saline and NGF-treated rats two hours after intravesical saline distention. Fos expression and CGRP-IR in NGF-treated rats with bladder distention was compared to that observed in cyclophosphamide (CYP; 75 mg/kg; i.p.) treated rats with bladder distention.</p> <p>Results</p> <p>Two-week infusion of NGF into the bladder wall increased bladder weight, reduced bladder capacity (60%), reduced the intercontraction interval (60%) and increased the amplitude of non-voiding contractions. NGF treatment and intravesical saline distention (2 hr) increased expression of Fos protein in L6-S1 spinal cord and altered the distribution pattern of Fos-IR cells. CGRP-IR in the lumbosacral spinal cord was also increased after NGF treatment.</p> <p>Conclusion</p> <p>These data suggest that NGF infusion into the bladder wall induces bladder overactivity, can reveal a "nociceptive" Fos expression pattern in the spinal cord in response to a non-noxious bladder stimulus and increases CGRP-IR in the lumbosacral spinal cord.</p

Validation of a modified rat model for erectile function evaluation

The in vivo model for evaluation of erectile function in rats and mice has been widely used to investigate pathophysiology and treatment modalities of erectile function. The model is technically challenging which limits its broad availability. We have recently introduced a simplified surgical technique for dissection of corporal bodies and developed a new method to achieve stable contact between the cavernous nerve and the stimulating electrode without the need to manipulate the nerve between stimulations using 2-component silicone glue. The goal of this study was to validate this new technique and describe in detail the technical aspects of the procedure so that researchers with basic microsurgery skills can adopt it

A Non-Anesthetized Mouse Model for Recording Sensory Urinary Bladder Activity

The goal of this study was to develop an in vivo awake mouse model for extracellular bladder sensory nerve recording. A bipolar 125-μm silver electrode was positioned under a single postganglionic bladder nerve. Efferent nerve signals were eliminated by tying off the postganglionic bladder nerve between the major pelvic ganglion and the recording electrode. Sensory nerve activity was measured in the conscious animals 48 h after surgery during continuous intravesical infusion of 0.9% saline/0.5% acetic acid followed by 0.5% acetic acid with capsazepine (10 μM) at a rate of 0.75 ml/h. Continuous infusion of 0.9% NaCl led to a gradual increase in the frequency of sensory nerve firing that peaked upon reaching threshold pressure. Non-micturition contractions were observed in some animals during filling and other animals exhibited only minimal pressure fluctuations; both types of events were associated with a rise in sensory nerve activity. Intravesical infusion of 0.5% acetic acid reduced the intermicturition interval. This was associated with a 2.1-fold increase in bladder pressure during filling and a two-fold increase at both threshold and micturition pressures. Concurrent with these changes, sensory activity increased 2.8-fold during filling and 2.4-fold at threshold pressure. Subsequent intravesical infusion of capsazepine in 0.5% acetic acid reduced filling and threshold pressures by 21 and 31.2%, respectively, and produced corresponding decreases of 36 and 23.4% in sensory nerve activity. The current study shows that multifiber sensory nerve recordings can be reproducibly obtained from conscious mice

The Importance of Aquaporin 1 in Pancreatitis and Its Relation to the CFTR Cl- Channel

Aquaporins (AQPs) facilitate the transepithelial water flow involved in epithelial fluid secretion in numerous tissues;however, their function in the pancreas is less characterized. Acute pancreatitis (AP) is a serious disorder in which specific treatment is still not possible. Accumulating evidence indicate that decreased pancreatic ductal fluid secretion plays an essential role in AP;therefore, the aim of this study was to investigate the physiological and pathophysiological role of AQPs in the pancreas. Expression and localization of AQPs were investigated by real-time PCR and immunocytochemistry, whereas osmotic transmembrane water permeability was estimated by the dye dilution technique, in Capan-1 cells. The presence of AQP1 and CFTR in the mice and human pancreas were investigated by immunohistochemistry. Pancreatic ductal HCO3- and fluid secretion were studied on pancreatic ducts isolated from wild-type (WT) and AQP1 knock out (KO) mice using microfluorometry and videomicroscopy, respectively. In vivo pancreatic fluid secretion was estimated by magnetic resonance imaging. AP was induced by intraperitoneal injection of cerulein and disease severity was assessed by measuring biochemical and histological parameters. In the mice, the presence of AQP1 was detected throughout the whole plasma membrane of the ductal cells and its expression highly depends on the presence of CFTR Cl- channel. In contrast, the expression of AQP1 is mainly localized to the apical membrane of ductal cells in the human pancreas. Bile acid treatment dose- and time-dependently decreased mRNA and protein expression of AQP1 and reduced expression of this channel was also demonstrated in patients suffering from acute and chronic pancreatitis. HCO3- and fluid secretion significantly decreased in AQP1 KO versus WT mice and the absence of AQP1 also worsened the severity of pancreatitis. Our results suggest that AQP1 plays an essential role in pancreatic ductal fluid and HCO3- secretion and decreased expression of the channel alters fluid secretion which probably contribute to increased susceptibility of the pancreas to inflammation

Abstracts from the 20th International Symposium on Signal Transduction at the Blood-Brain Barriers

https://deepblue.lib.umich.edu/bitstream/2027.42/138963/1/12987_2017_Article_71.pd

Exogenous overexpression of nerve growth factor in the urinary bladder produces bladder overactivity and altered micturition circuitry in the lumbosacral spinal cord-5

<p><b>Copyright information:</b></p><p>Taken from "Exogenous overexpression of nerve growth factor in the urinary bladder produces bladder overactivity and altered micturition circuitry in the lumbosacral spinal cord"</p><p>http://www.biomedcentral.com/1472-6793/7/9</p><p>BMC Physiology 2007;7():9-9.</p><p>Published online 28 Aug 2007</p><p>PMCID:PMC2000875.</p><p></p>, . Fluorescence photographs showing CGRP-IR in the L6 () and S1 () spinal segment of control (saline) + bladder distention. , . Fluorescence photographs showing CGRP-IR in the L6 () and S1 () spinal segment with NGF treatment + bladder distention. Increased density of CGRP-IR was observed in the medial (MDH) to lateral (LDH) extent of the superficial laminae (I-II) of the dorsal horn (DH) with NGF treatment in L6 () and S1 () segments. Changes in CGRP-IR in other spinal cord regions were more dramatic in the S1 spinal segment. Increased CGRP-IR was present in a fiber bundle extending from Lissauer's tract in lamina I along the lateral edge of the DH to the region of the sacral parasympathetic nucleus (SPN) (lateral collateral pathway of Lissauer, LCP) in the S1 segment (). Although this fiber bundle was present in control tissue sections, the staining was less intense () and was less frequently observed in transverse sections compared to NGF treatment (). Faint CGRP-IR was present in the region of the SPN in control sections (, ). With NGF treatment, CGRP-IR in the SPN region also increased in the S1 segment. Increased CGRP-IR was also present in the dorsal commissure (DCM) with NGF treatment (, , ). Summary bar graphs of CGRP-IR optical density (O.D.) as measured in specific regions of the L6-S1 spinal cord (, ). Calibration bar represents 125 μm. *, p ≤ 0.01

Exogenous overexpression of nerve growth factor in the urinary bladder produces bladder overactivity and altered micturition circuitry in the lumbosacral spinal cord-1

<p><b>Copyright information:</b></p><p>Taken from "Exogenous overexpression of nerve growth factor in the urinary bladder produces bladder overactivity and altered micturition circuitry in the lumbosacral spinal cord"</p><p>http://www.biomedcentral.com/1472-6793/7/9</p><p>BMC Physiology 2007;7():9-9.</p><p>Published online 28 Aug 2007</p><p>PMCID:PMC2000875.</p><p></p>ts (). Arrows point to some non-voiding bladder contractions. The x-axis represents the time (minutes, min) and the y-axis represents the intravesical pressure (cm HO). The amount of saline voided (ml) is also illustrated