- Molecular mechanisms of bi-directional ion transport in the Malpighian tubules of a lepidopteran crop pest, Trichoplusia ni. [Journal Article]
- JIJ Insect Physiol 2018 Jun 14
- Classical studies have described in detail the complex and regionalized morphology of the Malpighian tubule (MT) in larval Lepidoptera. Recent studies revealed unusual aspects of ion transport in the...
Classical studies have described in detail the complex and regionalized morphology of the Malpighian tubule (MT) in larval Lepidoptera. Recent studies revealed unusual aspects of ion transport in the Malpighian tubules of the larva of the cabbage looper, Trichoplusia ni. These included: cation reabsorption via secondary cells (SC); coupling of SCs to neighbouring PCs via gap junctions to enable reabsorption; and a reversal from cation secretion to reabsorption by the principal cells in the distal ileac plexus region of the in situ tubule in response to dietary ion loading. The current paper aimed to identify molecular components of ion transport in the MTs of T. ni and to describe their role in the recently reported reversal of ion transport in ion-loaded animals. Using a combination of molecular, immunohistochemical and electrophysiological techniques, we assigned roles to Na+/K+-ATPase (NKA), V-type H+-ATPase (VA), Na+/K+/Cl- co-transporter (NKCC), K+/Cl- co-transporter (KCC), inward-rectifying K+ channel (Kir), and Na+/H+ exchangers (NHE)-7 and -8 in the transport of Na+ and K+ by the distal ileac plexus of T. ni. The yellow region of the tubule lacked all of the above except VA, and the white region lacked all of the above transporters but expressed an amiloride-sensitive Na+ channel (NaC). Overall, the ion transport machinery in the distal ileac plexus of the T. ni tubule shows remarkable similarity to that in tubules of other groups of insects, yet this region transports ions very differently. Shutdown of secretory ATPases and utilisation of the same molecular machinery in the face of changing ion gradients may enable ion transport reversal in lepidopteran MTs. We propose that gap junction-based coupling of the two cell types likely aids in toggling between ion secretion and ion reabsorption in this segment.
- In vitro interaction and biocompatibility of titanate nanotubes with microglial cells. [Journal Article]
- TAToxicol Appl Pharmacol 2018 Jun 13
- Titanate nanotubes (TiONts) are promising agents for biomedical applications. Microglial activation and associated oxidative burst are major challenges in drug delivery applications across the brain....
Titanate nanotubes (TiONts) are promising agents for biomedical applications. Microglial activation and associated oxidative burst are major challenges in drug delivery applications across the brain. Here, TiONts were designed for drug delivery systems by functionalizing them with (3-aminopropyl) triethoxysilane (APTES), their interactions and biocompatibility were studied in vitro using murine microglial BV-2 cells. TiONts-APTES exposure resulted in increased ROS production and transient mitochondrial hyperpolarization. However, there was no indication of microglial proliferation in BV-2 cells as suggested by cell cycle analysis and cell count. The internalization process of TiONts-APTES into cells by endocytosis vesicles and passive diffusion were proved by transmission electron microscopy (TEM) with and without amiloride, the endocytosis inhibiting agent. In addition, the TiONts-APTES exhibited good biocompatibility on microglial BV-2 cells as revealed by the morphology and viability analysis.
- Topiramate is more effective than acetazolamide at lowering intracranial pressure. [Journal Article]
- CCephalalgia 2018 Jan 01; :333102418776455
- Background The management of idiopathic intracranial hypertension focuses on reducing intracranial pressure to preserve vision and reduce headaches. There is sparse evidence to support the use of som...
Background The management of idiopathic intracranial hypertension focuses on reducing intracranial pressure to preserve vision and reduce headaches. There is sparse evidence to support the use of some of the drugs commonly used to manage idiopathic intracranial hypertension, therefore we propose to evaluate the efficacy of these drugs at lowering intracranial pressure in healthy rats. Methods We measured intracranial pressure in female rats before and after subcutaneous administration of acetazolamide, topiramate, furosemide, amiloride and octreotide at clinical doses (equivalent to a single human dose) and high doses (equivalent to a human daily dose). In addition, we measured intracranial pressure after oral administration of acetazolamide and topiramate. Results At clinical and high doses, subcutaneous administration of topiramate lowered intracranial pressure by 32% ( p = 0.0009) and 21% ( p = 0.015) respectively. There was no significant reduction in intracranial pressure noted with acetazolamide, furosemide, amiloride or octreotide at any dose. Oral administration of topiramate significantly lowered intracranial pressure by 22% ( p = 0.018), compared to 5% reduction with acetazolamide ( p = >0.999). Conclusion Our in vivo studies demonstrated that both subcutaneous and oral administration of topiramate significantly lowers intracranial pressure. Other drugs tested, including acetazolamide, did not significantly reduce intracranial pressure. Future clinical trials evaluating the efficacy and side effects of topiramate in idiopathic intracranial hypertension patients would be of interest.
- The immediate influence of deltamethrin on ion transport through rabbit skin. An in vitro study. [Journal Article]
- PBPestic Biochem Physiol 2018; 148:144-150
- Deltamethrin can be absorbed into the respiratory tract, the gastrointestinal tract and through the skin. The study was designed to assess the effect of deltamethrin on electrophysiological parameter...
Deltamethrin can be absorbed into the respiratory tract, the gastrointestinal tract and through the skin. The study was designed to assess the effect of deltamethrin on electrophysiological parameters of rabbit's skin, studied in vitro, to identify the mechanism of action and effects of short-term dermal exposure to deltamethrin. The objective of the study was to investigate changes in electrophysiological parameters after exposure to 0.01 M deltamethrin under unchanged conditions, in the presence of amiloride (sodium transport blocker) and bumetanide (chloride transport blocker). Exposure to deltamethrin reduced the electrophysiological reaction of examined tissue in unchanged conditions and during the sodium reabsorption phase but did not influence the chloride ion secretion phase. The presented data show that the pyrethroide affects transepithelial ion transport in the external layers of the skin. The inhibition of chloride and sodium ions enabled evaluation of the impact of the pesticide on dermal transport.
- A two-phase response of endothelial cells to hydrostatic pressure. [Journal Article]
- JCJ Cell Sci 2018 May 30
- The vascular endothelium is exposed to three types of mechanical forces: blood flow-mediated shear stress, vessel-diameter dependent wall tension and hydrostatic pressure. Despite considerable variat...
The vascular endothelium is exposed to three types of mechanical forces: blood flow-mediated shear stress, vessel-diameter dependent wall tension and hydrostatic pressure. Despite considerable variations of blood pressure in normal and pathological physiology, little is known about the acute molecular and cellular effects of hydrostatic pressure on endothelial cells. Here, we used a combination of quantitative fluorescence microscopy, atomic force microscopy and molecular perturbations to characterize the specific response of endothelial cells to pressure application. We identified a two-phase response of endothelial cells to acute (1 h) vs. chronic (24 h) pressure application (100 mmHg). While both regimes induce cortical stiffening, the acute response is linked to calcium-mediated myosin activation, whereas the chronic cell response is dominated by increased cortical actin density and a loss in endothelial barrier function. GsMTx-4 and amiloride inhibit the acute pressure response, which suggest the sodium channel ENaC as key player in endothelial pressure sensing. The described two-phase pressure response may participate in the differential effects of transient changes in blood pressure and hypertension.
- Depletion of Cholesterol Reduces ENaC Activity by Decreasing Phosphatidylinositol-4,5-Bisphosphate in Microvilli. [Journal Article]
- CPCell Physiol Biochem 2018 May 24; 47(3):1051-1059
- CONCLUSIONS: Since PIP2 can directly stimulate ENaC and also affect ENaC trafficking, these data suggest that depletion of Cho reduces ENaC apical density and activity at least in part by decreasing PIP2 in the microvilli.
- The Effects of Diuretics on Mineral and Bone Metabolism. [Journal Article]
- PEPediatr Endocrinol Rev 2018; 15(4):291-297
- The effects of diuretics on water and electrolyte metabolism are well-established, but less known to the clinician are their effects on bone and mineral metabolism, and in particular on that of calci...
The effects of diuretics on water and electrolyte metabolism are well-established, but less known to the clinician are their effects on bone and mineral metabolism, and in particular on that of calcium homeostasis. In general, and clinically most relevant, diuretics acting at the thick ascending limb of the loop of Henle cause loss of calcium into the urine, thus making them a useful tool in treating hypercalcemia. However the hypercalciuria caused by loop diuretics may lead to the development of urolithiasis and nephrocalcinosis, as well as secondary hyperparathyroidism and bone disease. On the other hand, thiazide diuretics that act more distally, increase tubular calcium reabsorption, thus providing protection against hypercalciuria, and with that may raise serum calcium, suppress PTH secretion and improve bone metabolism. Additional hypocalciuric effect may be observed with the use of potassium-sparing diuretics. This review will address the effects of diuretics on mineral metabolism in the kidney and consequently on systemic mineral and bone metabolism.
- Inhibitor analysis revealed that clathrin-mediated endocytosis is involed in cellular entry of type III grass carp reovirus. [Journal Article]
- VJVirol J 2018 05 24; 15(1):92
- CONCLUSIONS: Taken together, our data have suggested that GCRV104 enters CIK cells through clathrin-mediated endocytosis in a pH-dependent manner. We also suggest that dynamin is critical for efficient viral entry. Additionally, the phosphatidylinositol 3-kinase inhibitor wortmannin and the protein kinase C inhibitor rottlerin block GCRV104 cell entry and replication.
- Acid-sensing ion channels: dual function proteins for chemo-sensing and mechano-sensing. [Review]
- JBJ Biomed Sci 2018 May 24; 25(1):46
- CONCLUSIONS: Together, ASICs are dual-function proteins for both chemosensation and mechanosensation involved in monitoring physiological homoeostasis and pathological signals.
New Search Next
- Liddle's-like syndrome associated with nephrotic syndrome secondary to membranous nephropathy: the first case report. [Journal Article]
- BNBMC Nephrol 2018 May 23; 19(1):122
- CONCLUSIONS: We reported for the first time a case of Liddle's-like syndrome associated with nephrotic syndrome secondary to MN. Aberrant activation of ENaC was suggested transient during the period of high proteinuria, and the activation was reversible with a decrease in proteinuria.