Low pressure voiding induced by stimulation and 1  kHz post-stimulation block of the Pudendal nerves in cats

Exp Neurol. 2021 Sep 3:113860. doi: 10.1016/j.expneurol.2021.113860. Online ahead of print.ABSTRACTThe goal of this study is to induce low-pressure voiding by stimulation and bilateral 1 kHz post-stimulation block of the pudendal nerves. In anesthetized cats, wire hook electrodes were placed on the left and/or right pudendal nerves. Stimulus pulses (30 Hz, 0.2 ms) were applied to one pudendal nerve to induce a reflex bladder contraction and to produce contractions of the external urethral sphincter (EUS). High frequency (1 kHz) biphasic stimulation was applied to block axonal conduction in both pudendal nerves and block EUS activity. In 4 cats, a catheter was inserted into the distal urethra to perfuse and measure the back pressure caused by the EUS contraction. In another 5 cats, a catheter was inserted into the bladder dome and the urethra was left open to allow voiding. The 1 kHz stimulation (30-60 s, 0.5-5 mA) delivered via a wire hook electrode completely blocked pudendal nerve conduction for ≥2 min after terminating the stimulation, i.e., a post-stimulation block. The block gradually disappeared in 6-18 min. The block duration increased with increasing amplitude or duration of the 1 kHz stimulation. Without the 1 kHz block, 30 Hz stimulation alone induced high-pressure (90 cmH2O) voiding. When combined with the 1 kHz block, the 30 Hz stimulation induced low-pressure (≤50 cmH2O) voiding with a high voiding efficiency (80%). In summary, a minimally invasive surgical...
Source: Experimental Neurology - Category: Neurology Authors: Source Type: research

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This study reports a novel idea to restore both continence and micturition after SCI by an implantable pudendal nerve stimulator (PNS). The PNS was surgically implanted in four cats with complete SCI at T9-T10 spinal level and tested weekly for 13-14 weeks under awake conditions. These chronic SCI cats consistently exhibited large residual bladder volumes (average 40-50 ml) due to their inability to void efficiently, while urine leakage also occurred frequently. The PNS which consisted of stimulating the pudendal nerve at 20-30 Hz to trigger a spinal reflex bladder contraction and at the same time blocking the pudendal ner...
Source: Experimental Neurology - Category: Neurology Authors: Source Type: research
Abstract Moderate acute intermittent hypoxia (AIH) elicits a persistent, serotonin-dependent increase in phrenic amplitude, known as phrenic long-term facilitation (pLTF). Although pLTF was originally demonstrated by carotid sinus nerve stimulation, AIH still elicits residual pLTF in carotid denervated rats (CBX) via a distinct, but unknown mechanism. We hypothesized that exaggerated hypoxia-induced hypotension after CBX, leading to greater spinal tissue hypoxia and extracellular adenosine accumulation, thereby triggering adenosine 2A receptor (A2A)-dependent pLTF. Phrenic activity, arterial pressure and spinal ti...
Source: Experimental Neurology - Category: Neurology Authors: Tags: Exp Neurol Source Type: research
ConclusionsDistal colon stimulation evoked colonic activity. The dependence of this response on stimulation location and anesthesia suggests that responses were reflex mediated. Colonic stimulation may have the potential to improve colonic motility for individuals with neurogenic bowel dysfunction.
Source: Neuromodulation: Technology at the Neural Interface - Category: Biotechnology Authors: Tags: Basic Research Source Type: research
In this study, spontaneous baroreflex sensitivity (SBRS) was also calculated through the sequence method by the computer software CardioSeries (v2.4). A baroreflex sequence was defined as a sequence of at least four heart beats in which both systolic arterial pressure and pulse interval increased (up sequences) or decreased (down sequences) as previously described (Braga et al., 2008). Evaluation of Sympathetic Tonus to the Vasculature In a separate group of rats, the sympathetic vascular tone was evaluated by an intravenous injection of hexamethonium (30 mg/Kg, Sigma-Aldrich, São Paulo, Brazil), a ganglionic bloc...
Source: Frontiers in Physiology - Category: Physiology Source Type: research
We examined the expression of TRPV1 in peripheral tissue and DRG neurons of CPIP model rats and we studied whether CPIP model could induce peripheral sensitization of TRPV1 channel and enhance DRG neuron excitability. Then we examined the therapeutic effects of locally applied TRPV1 specific antagonist AMG9810 on pain responses of CPIP model rats. Lastly, we explored the effects of AMG9810 on DRG neuron hyperexcitability and spinal glial activation induced by CPIP. Our results demonstrate that TRPV1 plays an important role in mediating the behavioral hypersensitivity of CPIP model rats via promoting peripheral nociceptor a...
Source: Frontiers in Pharmacology - Category: Drugs & Pharmacology Source Type: research
Conclusions: In vivo exposure to remifentanil exerts a beneficial effect against excitotoxicity on the developing mouse brain, which is associated with a reduction in the size of ibotenate-induced brain lesion as well as prevention of some behavioral deficits in young mice. The long-term effect of neonatal exposure to remifentanil should be investigated. Introduction The potential neurotoxicity of anesthetics in the perinatal period prompted the US Food and Drug Administration (FDA) to release a drug safety communication warning in 2016 that stated, “repeated or lengthy use of general anesthetics or sedation ...
Source: Frontiers in Neurology - Category: Neurology Source Type: research
In conclusion, the site of action of σ1R for opioid modulation on acute thermal nociception is located at the peripheral and supraspinal levels, and the opioid-potentiating effect is independent of the spinal noradrenaline increase produced by S1RA. Introduction The sigma-1 receptor (σ1R) has been described as the first ligand-regulated molecular chaperone located at the endoplasmic reticulum and plasma membranes whose activity is regulated in an agonist-antagonist manner. The σ1R is expressed in key areas for pain control and there is cumulative evidence supporting an involvement of the σ1R...
Source: Frontiers in Pharmacology - Category: Drugs & Pharmacology Source Type: research
This study not only provides biological evidence to support the use of duloxetine as the first standard CIPN drug but will also lead to potential new targets for CIPN drug development. Introduction A major dose-limiting complication of chemotherapy is chemotherapy-induced peripheral neuropathy (CIPN). The greatest contributors to CIPN are taxanes (e.g., paclitaxel) and platinum-based (e.g., oxaliplatin) treatments (Krukowski et al., 2015). Paclitaxel (PTX) can effectively treat several of the most common cancers including breast cancer, lung cancer, and ovarian cancer (Ewertz et al., 2015; Cetinkaya-Fisgin et al., ...
Source: Frontiers in Pharmacology - Category: Drugs & Pharmacology Source Type: research
Abstract Autonomic dysreflexia (AD) often occurs in individuals living with spinal cord injury (SCI) and is characterized by uncontrolled hypertension in response to otherwise innocuous stimuli originating below the level of the spinal lesion. Visceral stimulation is a predominate cause of AD in humans, and effectively replicates the phenotype in rodent models of SCI. Direct assessment of sympathetic responses to viscerosensory stimulation in spinalized animals is challenging and requires invasive surgical procedures necessitating the use of anesthesia. However, administration of anesthesia markedly affects viscer...
Source: American Journal of Physiology. Heart and Circulatory Physiology - Category: Physiology Authors: Tags: Am J Physiol Heart Circ Physiol Source Type: research
This article is protected by copyright. All rights reserved. PMID: 30689208 [PubMed - as supplied by publisher]
Source: The Journal of Physiology - Category: Physiology Authors: Tags: J Physiol Source Type: research
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