scholarly journals Role of gap junctions in spontaneous activity of the rat bladder

2007 ◽  
Vol 293 (4) ◽  
pp. F1018-F1025 ◽  
Author(s):  
Y. Ikeda ◽  
C. Fry ◽  
F. Hayashi ◽  
D. Stolz ◽  
D. Griffiths ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Gap Junction ◽  
Spontaneous Activity ◽  
Lamina Propria ◽  
Urothelial Cells ◽  
Frozen Sections ◽  
Sprague Dawley ◽  
Female Adult ◽  
Sprague Dawley Rats

Increased gap junction expression in lamina propria myofibroblasts and urothelial cells may be involved in detrusor overactivity, leading to incontinence. Immunohistochemistry was used to compare connexin (Cx) 26, 43, and 45 expression in the bladders of neonatal, adult, and spinal cord-transected rats, while optical imaging was used to map the spread of spontaneous activity and the effects of gap junction blockade. Female adult Sprague-Dawley rats were deeply anesthetized, a laminectomy was performed, and the spinal cord was transected (T8/T9). After 14 days, their bladders and those of age-matched adults (4 mo old) and neonates (7–21 day old) were excised and studied immunohistochemically using frozen sections or optically using whole bladders stained with voltage- and Ca2+-sensitive dyes. The expression of Cx26 was localized to the urothelium, Cx43 to the lamina propria myofibroblasts, and Cx45 to the detrusor smooth muscle. While the expression of Cx45 was comparable in all bladders, the expression of Cx43 and Cx26 was increased in neonate and transected animals. In the bladders of adults, spontaneous activity was initiated at multiple sites, resulting in a lack of coordination. Alternatively, in neonate and transected animals spontaneous activity was initiated at a focal site near the dome and spread in a coordinated fashion throughout the bladder. Gap junction blockade (18β-glycyrrhetinic acid, 1 μM) abolished this coordinated activity but had no effect on the uncoordinated activity in adult bladders. These data suggest that coordinated spontaneous activity requires gap junction upregulation in urothelial cells and lamina propria myofibroblasts.

scholarly journals Characterization of ultrasound-mediated delivery of trastuzumab to normal and pathologic spinal cord tissue

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Paige Smith ◽  
Natalia Ogrodnik ◽  
Janani Satkunarajah ◽  
Meaghan A. O’Reilly
Keyword(s):  
Drug Delivery ◽  
Spinal Cord ◽  
Focused Ultrasound ◽  
Healthy Tissue ◽  
Spinal Cord Tissue ◽  
Sprague Dawley ◽  
Intense Staining ◽  
Her2 Breast Cancer ◽  
Sprague Dawley Rats ◽  
Blood Spinal Cord Barrier

AbstractExtensive studies on focused ultrasound (FUS)-mediated drug delivery through the blood–brain barrier have been published, yet little work has been published on FUS-mediated drug delivery through the blood-spinal cord barrier (BSCB). This work aims to quantify the delivery of the monoclonal antibody trastuzumab to rat spinal cord tissue and characterize its distribution within a model of leptomeningeal metastases. 10 healthy Sprague–Dawley rats were treated with FUS + trastuzumab and sacrificed at 2-h or 24-h post-FUS. A human IgG ELISA (Abcam) was used to measure trastuzumab concentration and a 12 ± fivefold increase was seen in treated tissue over control tissue at 2 h versus no increase at 24 h. Three athymic nude rats were inoculated with MDA-MB-231-H2N HER2 + breast cancer cells between the meninges in the thoracic region of the spinal cord and treated with FUS + trastuzumab. Immunohistochemistry was performed to visualize trastuzumab delivery, and semi-quantitative analysis revealed similar or more intense staining in tumor tissue compared to healthy tissue suggesting a comparable or greater concentration of trastuzumab was achieved. FUS can increase the permeability of the BSCB, improving drug delivery to specifically targeted regions of healthy and pathologic tissue in the spinal cord. The achieved concentrations within the healthy tissue are comparable to those reported in the brain.

scholarly journals Mild DOCA-salt hypertension: sympathetic system and role of renal nerves

2011 ◽  
Vol 300 (5) ◽  
pp. H1781-H1787 ◽  
Author(s):  
Sachin S. Kandlikar ◽  
Gregory D. Fink
Keyword(s):  
Control Period ◽  
Whole Body ◽  
Renal Nerves ◽  
Experimental Hypertension ◽  
Sympathetic Activation ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Salt Hypertension ◽  
Hypertension Development

Excess sympathetic nervous system activity (SNA) is linked to human essential and experimental hypertension. To test whether sympathetic activation is associated with a model of deoxycorticosterone acetate (DOCA)-salt hypertension featuring two kidneys and a moderate elevation of blood pressure, we measured whole body norepinephrine (NE) spillover as an index of global SNA. Studies were conducted in chronically catheterized male Sprague-Dawley rats drinking water containing 1% NaCl and 0.2% KCl. After a 7-day surgical recovery and a 3-day control period, a DOCA pellet (50 mg/kg) was implanted subcutaneously in one group of rats (DOCA), while the other group underwent sham implantation (Sham). NE spillover was measured on control day 2 and days 7 and 14 after DOCA administration or sham implantation. During the control period, mean arterial pressure (MAP) was similar in Sham and DOCA rats. MAP was significantly increased in the DOCA group compared with the Sham group after DOCA administration ( day 14: Sham = 109 ± 5.3, DOCA = 128 ± 3.6 mmHg). However, plasma NE concentration, clearance, and spillover were not different in the two groups at any time. To determine whether selective sympathetic activation to the kidneys contributes to hypertension development, additional studies were performed in renal denervated (RDX) and sham-denervated (Sham-DX) rats. MAP, measured by radiotelemetry, was similar in both groups during the control and DOCA treatment periods. In conclusion, global SNA is not increased during the development of mild DOCA-salt hypertension, and fully intact renal nerves are not essential for hypertension development in this model.

Chronic intravenous administration of V1 arginine vasopressin agonist results in sustained hypertension

1994 ◽  
Vol 267 (2) ◽  
pp. H751-H756 ◽  
Author(s):  
A. W. Cowley ◽  
E. Szczepanska-Sadowska ◽  
K. Stepniakowski ◽  
D. Mattson
Keyword(s):  
Body Weight ◽  
Arginine Vasopressin ◽  
Plasma Catecholamines ◽  
Plasma Osmolality ◽  
Sprague Dawley ◽  
Prolonged Administration ◽  
Chronic Stimulation ◽  
Sustained Hypertension ◽  
Sprague Dawley Rats

Despite the well-recognized vasoconstrictor and fluid-retaining actions of vasopressin, prolonged administration of arginine vasopressin (AVP) to normal animals or humans fails to produce sustained hypertension. The present study was performed to elucidate the role of the V1 receptor in determining the ability of AVP to produce sustained hypertension. Conscious Sprague-Dawley rats with implanted catheters were infused with the selective V1 agonist, [Phe2,Ile3,Orn8]vasopressin (2 ng.kg-1.min-1), for 14 days in amounts that were acutely nonpressor. Blood pressure (MAP), heart rate (HR), body weight, and water intake (WI) were determined daily. Plasma AVP, plasma catecholamines norepinephrine and epinephrine, plasma osmolality, and electrolyte concentration were determined before and on days 1 and 7 of infusion. MAP increased significantly by 10.4 +/- 4.5 mmHg on day 1 and rose to 22 +/- 5 mmHg above control by day 14 (transient decrease on days 6-9) and then fell to control levels after the infusion was stopped. HR did not change significantly. Plasma AVP immunoreactivity increased from 2.5 +/- 0.3 to 10.9 +/- 2.1 pg/ml, whereas norepinephrine tended to fall only on day 1, with epinephrine only slightly elevated on day 7. No evidence of fluid retention was found, and rats lost sodium only on the first day of V1 agonist infusion. Body weight increased throughout the study but was unrelated to the changes of MAP. We conclude that chronic stimulation of V1 receptors results in sustained hypertension in rats.

Postjunctional supersensitivity of the rat vas deferens and gap junctions

1976 ◽  
Vol 54 (3) ◽  
pp. 412-416 ◽  
Author(s):  
D. M. Paton ◽  
J. Buckland-Nicks ◽  
A. Johns
Keyword(s):  
Electron Microscopy ◽  
Gap Junctions ◽  
Spontaneous Activity ◽  
Vas Deferens ◽  
Rat Vas Deferens ◽  
Sprague Dawley ◽  
Glutaraldehyde Fixation ◽  
Sprague Dawley Rats

Tissues from the duodenum and vas deferens of Sprague–Dawley rats were examined of the rat vas deferens and gap junctions. Can. J. Physiol. Pharmacol. 54, 412–416. by electron microscopy after glutaraldehyde fixation and postosmication. Gap junctions (nexuses) were readily demonstrated in the duodenum in both control and reserpine treated animals (1.0 mg/kg per day for 7 days). However, gap junctions could not be demonstrated in vas deferens. It is concluded that the postjunctional supersensitivity and spontaneous activity induced by reserpine in vas deferens, does not result from the formation of gap junctions.

The Hepatoprotective Role of Warburgia salutaris and Iso-Mukaadial Acetate on Carbon tetrachloride Intoxicated Rats Model

2021 ◽  
Vol 17 ◽  
Author(s):  
Gideon Ayeni ◽  
Mthokozisi Blessing Cedric Simelane ◽  
Shahidul Islam ◽  
Ofentse Jacob Pooe
Keyword(s):  
Carbon Tetrachloride ◽  
Hepatic Injury ◽  
Antioxidant Properties ◽  
Hepatic Necrosis ◽  
Protective Role ◽  
Dependent Manner ◽  
Sprague Dawley ◽  
Sprague Dawley Rats ◽  
Isolated Compound

Background: Medicinal plants together with their isolated bioactive compounds are known for their antioxidant properties which constitute therapeutic agents that are routinely employed in the treatment of liver diseases. Aims of the Study: The current study sought to explore the protective role of Warburgia salutaris and its isolated compound, iso-mukaadial acetate against carbon tetrachloride (CCl4)-induced hepatic injury. Methods: Thirty-five male Sprague Dawley rats were divided into seven groups of five animals each and injected with CCl4 to induce hepatic injury. Results: Treatment with the crude extract of W. salutaris and of iso-mukaadial acetate significantly reduced the levels of alkaline phosphatase, alanine and aspartate aminotransaminases, total bilirubin and malondialdehyde in a dose dependent manner, when compared to untreated groups. Liver histology revealed a reduction in hepatic necrosis and inflammation. Conclusion: The current investigation has demonstrated that W. salutaris extract and iso-mukaadial acetate could mitigate the acute liver injury inflicted by a hepatotoxic inducer in rats.

scholarly journals Transient Neonatal Cryptosporidium parvum Infection Triggers Long-Term Jejunal Hypersensitivity to Distension in Immunocompetent Rats

2006 ◽  
Vol 74 (7) ◽  
pp. 4387-4389 ◽  
Author(s):  
Rachel Marion ◽  
Asiya Baishanbo ◽  
Gilles Gargala ◽  
Arnaud François ◽  
Philippe Ducrotté ◽  
...  
Keyword(s):  
Cryptosporidium Parvum ◽  
Myeloperoxidase Activity ◽  
Sprague Dawley ◽  
Depressor Response ◽  
Sprague Dawley Rats

ABSTRACT In 5-day-old immunocompetent Sprague-Dawley rats infected with either 102 or 105 Cryptosporidium parvum oocysts, transient infection resulted 120 days later in increased cardiovascular depressor response to jejunal distension and jejunal myeloperoxidase activity (P < 0.05). Nitazoxanide treatment normalized jejunal sensitivity (P < 0.001) but not myeloperoxidase levels (P > 0.05). Data warrant further evaluation of the role of early cryptosporidiosis in the development of chronic inflammatory gut conditions.

scholarly journals Olfactory bulb transplantation in complete spinal cord injury: axonal regeneration and locomotor recovery

2015 ◽  
Vol 14 (1) ◽  
pp. 50-52
Author(s):  
Carlos Abraham Arellanes-Chávez ◽  
Ariana Martínez Bojórquez ◽  
Ernesto Ramos Martínez
Keyword(s):  
Spinal Cord ◽  
Axonal Regeneration ◽  
Sufficient Evidence ◽  
Spinal Cord Regeneration ◽  
Sprague Dawley ◽  
Locomotor Recovery ◽  
Randomized Controlled ◽  
Sprague Dawley Rats ◽  
Cord Injury ◽  
Complete Spinal Cord Injury

OBJECTIVES: To determine whether the intervention in rats is effective in terms of spinal cord regeneration and locomotor recovery, in order to obtain sufficient evidence to apply the therapy in humans. METHODS: a randomized, controlled, experimental, prospective, randomized trial was conducted, with a sample of 15 adult female Sprague-Dawley rats weighing 250 gr. They were divided into three equal groups, and trained for 2 weeks based on Pavlov's classical conditioning method, to strengthen the muscles of the 4 legs, stimulate the rats mentally, and keep them healthy for the surgery. RESULTS: It was observed that implantation of these cells into the site of injury may be beneficial to the process of spinal cord regeneration after spinal trauma, to mediate secretion of neurotrophic and neuroprotective chemokines, and that the OECs have the ability to bridge the repair site and decrease the formation of gliosis, creating a favorable environment for axonal regeneration. CONCLUSION: It is emphasized that the olfactory ensheathing glial cells possess unique regenerative properties; however, it was not until recently that the activity of promoting central nervous system regeneration was recognized.

Recombinant human regenerating gene 4 attenuates the severity of osteoarthritis by promoting the proliferation of articular chondrocyte in an animal model

2021 ◽  
Vol 14 ◽  
Author(s):  
Xue-jia Li ◽  
Fei Zhu ◽  
Bo Li ◽  
Dong Zhang ◽  
Cheng-Wei Liang
Keyword(s):  
Risk Factors ◽  
Animal Model ◽  
Sprague Dawley ◽  
Articular Chondrocyte ◽  
Chondrocyte Proliferation ◽  
Histological Changes ◽  
Proper Role ◽  
Sprague Dawley Rats ◽  
Gene 4

Introduction: Osteoarthritis (OA) is a dominant cause of morbidity and disability. As a chronic disease, its etiological risk factors and most therapies at present, are empirical and symptomatic. Regenerating gene 4 (Reg4) is involved in cell growth, survival, regeneration, adhesion, and resistance to apoptosis, which are partially thought to be the pathogenic mechanisms of OA. However, the proper role of Reg4 in OA is still unknown. Methods: In this study, a consecutive administration of rhReg4 was applied to normal Sprague-Dawley rats or rats after OA induction. Histological changes and chondrocyte proliferation in the articular cartilage were measured. Results: We found that RhReg4 promotes chondrocyte proliferation in normal rats, and RhReg4 attenuated the severity of OA in rats by promoting chondrocytes’ proliferation in OA rats. Conclusion: In conclusion, recombinant human regenerating gene 4 (rhReg4) attenuates the severity of osteoarthritis in OA animal models and may be used as a new method for the treatment of osteoarthritis.

Carvacrol attenuates amikacin-induced nephrotoxicity in the rat

2021 ◽  
Author(s):  
Atta Mohammad Dost ◽  
Mehmet Gunata ◽  
Onural Ozhan ◽  
Azibe Yildiz ◽  
Nigar Vardi ◽  
...  
Keyword(s):  
Inflammatory Cell ◽  
Kidney Tissue ◽  
Control Group ◽  
Histopathological Changes ◽  
Sprague Dawley ◽  
Tissue Samples ◽  
Sprague Dawley Rats ◽  
Before And After ◽  
Per Oral

Abstract Amikacin (AK) is frequently used in the treatment of gram-negative and some gram-positive infections. However, its use is limited due to nephrotoxicity due to the increase in reactive oxygen radicals. The aim of this study was to investigate the role of carvacrol (CAR) against AK-induced nephrotoxicity in rats. Thirty-two Sprague Dawley rats were randomly divided into four groups as control (Vehicle), AK (400 mg/kg), CAR + AK (80 mg/kg CAR + 400 mg/kg AK), and AK + CAR (400 mg/kg AK + 80 mg/kg CAR) groups. AK and CAR were administered via intramuscular and per-oral for 7 days, respectively. Blood and kidney tissue samples were taken at the end of the experiment. Renal function and histopathological changes were compared, and the relevant parameters of oxidative stress and inflammation were detected. Histopathological findings (necrotic changes and dilatation and inflammatory cell infiltration) significantly increased in the AK group compared to the control group. Also, the rats in the AK group lost weight significantly. It was found that CAR treatment before and after AK significantly improved nephrotoxicity histopathologically (p < 0.05). However, this improvement was not detected biochemically. These results show that CAR treatment before and after AK improves nephrotoxicity in the histopathological level.

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