Dataset Information

Influence of sildenafil on the purinergic components of nerve-mediated and urothelial ATP release from the bladder of normal and spinal cord injured mice.

ABSTRACT: BACKGROUND AND PURPOSE:PDE inhibitors such as sildenafil alleviate lower urinary tract symptoms; however, a complete understanding of their action on the bladder remains unclear. We are investigating the effects of sildenafil, on post and preganglionic nerve-mediated contractions of the mouse bladder, and neuronal and urothelial ATP release. EXPERIMENTAL APPROACH:Bladders were used from young (12 weeks), aged (24 months), and spinal cord transected (SCT), mice, for in vitro contractility experiments. An arterially perfused in situ whole mouse model was used to record bladder pressure. Nerve-mediated contractions were generated by electrical field stimulation (EFS) of postganglionic nerve terminals or the pelvic nerve. ATP release during EFS in intact detrusor strips, and during stretch of isolated mucosa strips, was measured using a luciferin-luciferase assay. KEY RESULTS:Sildenafil (20 ?M) inhibited nerve-mediated contractions in young mice, with an increase in f1/2 values in force-frequency relationships, demonstrating a greater effect at low frequencies. Sildenafil reduced the atropine-resistant, purinergic component of nerve-mediated contractions, and suppressed neuronal ATP release upon EFS in vitro. Sildenafil reduced the preganglionic pelvic nerve stimulated bladder pressure recordings in situ; comparable to in vitro experiments. Sildenafil reduced stretch-induced urothelial ATP release. Sildenafil also relaxed nerve-mediated contractions in aged and SCT mice. CONCLUSION AND IMPLICATIONS:Sildenafil has a greater effect on the low-frequency, purinergic-mediated contractions and suppresses neuronal ATP release. In addition, sildenafil reduces stretch-induced urothelial ATP release. These results demonstrate a novel action of sildenafil to selectively inhibit ATP release from nerve terminals innervating detrusor smooth muscle and the urothelium.

SUBMITTER: Chakrabarty B

PROVIDER: S-EPMC6555867 | biostudies-literature | 2019 Jul

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Influence of sildenafil on the purinergic components of nerve-mediated and urothelial ATP release from the bladder of normal and spinal cord injured mice.

Chakrabarty Basu B Ito Hiroki H Ximenes Manuela M Nishikawa Nobuyuki N Vahabi Bahareh B Kanai Anthony J AJ Pickering Anthony E AE Drake Marcus J MJ Fry Christopher H CH

British journal of pharmacology 20190511 13

<h4>Background and purpose</h4>PDE inhibitors such as sildenafil alleviate lower urinary tract symptoms; however, a complete understanding of their action on the bladder remains unclear. We are investigating the effects of sildenafil, on post and preganglionic nerve-mediated contractions of the mouse bladder, and neuronal and urothelial ATP release.<h4>Experimental approach</h4>Bladders were used from young (12 weeks), aged (24 months), and spinal cord transected (SCT), mice, for in vitro contra ...[more]

PMID: 30924527

Similar Datasets

Project description:ObjectiveSpinal cord injury (SCI) affects a quarter million individuals in the United States, and there is currently no clinical treatment. Both fresh and acellular peripheral nerve grafts can induce spinal axon regeneration and support functional recovery in experimental injury models. Nonetheless, a scaffold that can be injected into a spinal contusion would be far less invasive to apply. We aimed to develop the first injectable acellular nerve graft for promoting repair after contusion SCI.ApproachWe report a method to enzymatically solubilize optimized acellular (OA) nerve-a decellularized peripheral nerve graft developed in our laboratory and currently used clinically-to obtain an injectable solution that undergoes thermal gelation under physiological conditions. We quantified multiple physical and compositional properties of this novel material as well as tested its efficacy at acute and chronic time points following cervical contusion SCI.Main resultsThis injectable optimized acellular (iOA) nerve graft retains native chemical cues such as collagens and glycosaminoglycans. By varying hydrogel concentration, the rheological properties and compressive modulus of iOA were similar to that previous reported for rat central nervous tissue. iOA solution was compatible with rat Schwann cells in culture, and hydrogel injection into a rat cervical contusion model significantly reduced the ratio of M1:M2 macrophages after one week, favoring regenerative phenotypes (p < 0.05). Furthermore, while iOA treatment did not affect locomotor or respiratory recovery over an eight week period, the percentage of axonal coverage increased at the distal tissue interface (p < 0.05), suggesting enhanced axonal extension within this region.SignificanceOur data indicate that this novel injectable form of acellular nerve grafts is amenable for use after contusion SCI and may bolster a simultaneous therapy by acutely modulating the inflammatory milieu and supporting axonal growth.

Project description:Promoting the combination of robust regeneration of damaged axons and synaptic reconnection of these growing axon populations with appropriate neuronal targets represents a major therapeutic goal following spinal cord injury (SCI). A key impediment to achieving this important aim includes an intrinsic inability of neurons to extend axons in adult CNS, particularly in the context of the chronically-injured spinal cord. We tested whether an inhibitory peptide directed against phosphatase and tensin homolog (PTEN: a central inhibitor of neuron-intrinsic axon growth potential) could restore inspiratory diaphragm function by reconnecting critical respiratory neural circuitry in a rat model of chronic cervical level 2 (C2) hemisection SCI. We found that systemic delivery of PTEN antagonist peptide 4 (PAP4) starting at 8 weeks after C2 hemisection promoted substantial, long-distance regeneration of injured bulbospinal rostral Ventral Respiratory Group (rVRG) axons into and through the lesion and back toward phrenic motor neurons (PhMNs) located in intact caudal C3-C5 spinal cord. Despite this robust rVRG axon regeneration, PAP4 stimulated only minimal recovery of diaphragm function. Furthermore, re-lesion through the hemisection site completely removed PAP4-induced functional improvement, demonstrating that axon regeneration through the lesion was responsible for this partial functional recovery. Interestingly, there was minimal formation of putative excitatory monosynaptic connections between regrowing rVRG axons and PhMN targets, suggesting that (1) limited rVRG-PhMN synaptic reconnectivity was responsible at least in part for the lack of a significant functional effect, (2) chronically-injured spinal cord presents an obstacle to achieving synaptogenesis between regenerating axons and post-synaptic targets, and (3) addressing this challenge is a potentially-powerful strategy to enhance therapeutic efficacy in the chronic SCI setting. In conclusion, our study demonstrates a non-invasive and transient pharmacological approach in chronic SCI to repair the critically-important neural circuitry controlling diaphragmatic respiratory function, but also sheds light on obstacles to circuit plasticity presented by the chronically-injured spinal cord.

Dataset Information

Influence of sildenafil on the purinergic components of nerve-mediated and urothelial ATP release from the bladder of normal and spinal cord injured mice.

Publications

Influence of sildenafil on the purinergic components of nerve-mediated and urothelial ATP release from the bladder of normal and spinal cord injured mice.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets