Role of opioid and β-adrenergic receptors in bladder underactivity induced by prolonged pudendal nerve stimulation in cats.

Aims: To determine the role of opioid and β-adrenergic receptors in bladder underactivity induced by prolonged pudendal nerve stimulation (PNS).

Methods: In α-chloralose anesthetized cats, 30-min PNS was applied repeatedly for 3-9 times to induce poststimulation or persistent bladder underactivity. Then, naloxone (opioid receptor antagonist, 1 mg/kg, IV) or propranolol (β-adrenergic receptor antagonist, 3 mg/kg, IV) was given to reverse the bladder underactivity.

Pudendal Nerve Block by Adaptively Stepwise Increasing the Intensity of High-Frequency (10 kHz) Biphasic Stimulation.

Objective: The purpose of this study is to determine whether adaptively stepwise increasing the intensity of a high-frequency (10 kHz) biphasic stimulation (HFBS) can produce nerve conduction block without generating a large initial response.

Materials And Methods: In anesthetized cats, three cuff electrodes were implanted on the left pudendal nerve for stimulation or block. The urethral pressure increase induced by pudendal nerve stimulation was used to measure the pudendal nerve block induced by HFBS.

Therapeutic effects of p38 mitogen-activated protein kinase inhibition on hyperexcitability of capsaicin sensitive bladder afferent neurons in mice with spinal cord injury.

Aims: Nerve growth factor (NGF) has been implicated as a key molecule of pathology-induced changes in C-fiber afferent nerve excitability, which contributes to the emergence of neurogenic detrusor overactivity due to spinal cord injury (SCI). It is also known that the second messenger signaling pathways activated by NGF utilize p38 Mitogen-Activated Protein Kinase (MAPK). We examined the roles of p38 MAPK on electrophysiological properties of capsaicin sensitive bladder afferent neurons with SCI mice.

Model Analysis of Post-Stimulation Block of a Myelinated Axon by Direct Current.

Objective: To determine the role of ion concentrations and ion pump activity in conduction block of myelinated axon induced by a long-duration direct current (DC).

Methods: A new axonal conduction model for myelinated axons based on the classical Frankenhaeuser-Huxley (FH) equations is developed that includes ion pump activity and allows the intracellular and extracellular Na and K concentrations to change with axonal activity.

Results: Action potential generation, propagation, and acute DC block occurring within a short period (milliseconds) that do not significantly change the ion concentrations or trigger ion pump activity are successfully simulated by the new model in a similar way as the classical FH model.

Effect of high-frequency membrane potential alternation between depolarization and hyperpolarization on dorsal root ganglion neurons of rats.

The purpose of this study was to determine how sensory neurons respond to high-frequency membrane potential alternation between depolarization and hyperpolarization. Membrane currents were recorded from dissociated dorsal root ganglion (DRG) neurons of adult rats using the whole cell patch clamp technique in voltage clamp mode. Stepwise depolarization of the membrane was applied first to determine the threshold membrane potential for inducing an action potential (AP) current.

Current Knowledge and Novel Frontiers in Lower Urinary Tract Dysfunction after Spinal Cord Injury: Basic Research Perspectives.

This review article aims to summarize the recent advancement in basic research on lower urinary tract dysfunction (LUTD) following spinal cord injury (SCI) above the sacral level. We particularly focused on the neurophysiologic mechanisms controlling the lower urinary tract (LUT) function and the SCI-induced changes in micturition control in animal models of SCI. The LUT has two main functions, the storage and voiding of urine, that are regulated by a complex neural control system.

Penile Erection Induced by Stimulation of Sacral S1/S2 Spinal Root in Cats.

Objective: This study aimed at determining whether stimulation of sacral spinal roots can induce penile erection in cats.

Materials And Methods: In anesthetized cats, a 20-gauge catheter was inserted into the corpus cavernosum to measure the penile pressure. Stimulus pulses (5-80 Hz, 0.

Intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency biphasic stimulation.

A new axonal conduction model was used to analyze the interaction between intracellular sodium concentration and membrane potential oscillation in axonal conduction block induced by high-frequency (kHz) biphasic stimulation (HFBS).The model includes intracellular and extracellular sodium and potassium concentrations and ion pumps. First, the HFBS (1 kHz, 5.

Sacral neuromodulation of bladder underactivity induced by prolonged pudendal afferent firing in cats.

This study examined the effect of sacral neuromodulation on persistent bladder underactivity induced by prolonged pudendal nerve stimulation (PudNS). In 10 α-chloralose-anesthetized cats, repetitive application of 30-min PudNS induced bladder underactivity evident as an increase in bladder capacity during a cystometrogram (CMG). S1 or S2 dorsal root stimulation (15 or 30 Hz) at 1 or 1.

Temperature Effect on Nerve Conduction Block Induced by High-Frequency (kHz) Biphasic Stimulation.

Objectives: This study aims to determine temperature effect on nerve conduction block induced by high-frequency (kHz) biphasic stimulation (HFBS).

Materials And Methods: Frog sciatic nerve-muscle preparation was immersed in Ringer's solution at a temperature of 15 or 20 °C. To induce muscle contractions, a bipolar cuff electrode delivered low-frequency (0.

Superficial peroneal neuromodulation of nonobstructive urinary retention induced by prolonged pudendal afferent activity in cats.

The purpose of this study is to determine whether superficial peroneal nerve stimulation (SPNS) can improve nonobstructive urinary retention (NOUR) induced by prolonged pudendal nerve stimulation (PNS). In this exploratory acute study using eight cats under anesthesia, PNS and SPNS were applied by nerve cuff electrodes. Skin surface electrodes were also used for SPNS.

Defecation induced by stimulation of sacral S2 spinal root in cats.

The aim of this study was to determine whether stimulation of sacral spinal nerve roots can induce defecation in cats. In anesthetized cats, bipolar hook electrodes were placed on the S1-S3 dorsal and/or ventral roots. Stimulus pulses (1-50 Hz, 0.

High-frequency stimulation induces axonal conduction block without generating initial action potentials.

The purpose of this modeling study is to develop a novel method to block nerve conduction by high frequency biphasic stimulation (HFBS) without generating initial action potentials. An axonal conduction model including both ion concentrations and membrane ion pumps is used to analyze the axonal response to 1 kHz HFBS. The intensity of HFBS is increased in multiple steps while maintaining the intensity at a sub-threshold level to avoid generating an action potential.

Downstream projection of Barrington's nucleus to the spinal cord in mice.

Barrington's nucleus (Bar), which controls micturition behavior through downstream projections to the spinal cord, contains two types of projection neurons, Bar and Bar, that have different functions and target different spinal circuitry. Both types of neurons project to the L-S spinal intermediolateral (IML) nucleus, whereas Bar neurons also project to the dorsal commissural nucleus (DCN). To obtain more information about the spinal circuits targeted by Bar, we used patch-clamp recording in spinal slices from adult mice in combination with optogenetic stimulation of Bar terminals.

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

The 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.

Mechanisms Underlying Poststimulation Block Induced by High-Frequency Biphasic Stimulation.

Objective: To reveal the possible mechanisms underlying poststimulation block induced by high-frequency biphasic stimulation (HFBS).

Materials And Methods: A new axonal conduction model is developed for unmyelinated axons. This new model is different from the classical axonal conduction model by including both ion concentrations and membrane ion pumps to allow analysis of axonal responses to long-duration stimulation.

Deciphering Spinal Endogenous Dopaminergic Mechanisms That Modulate Micturition Reflexes in Rats with Spinal Cord Injury.

Spinal neuronal mechanisms regulate recovered involuntary micturition after spinal cord injury (SCI). It was recently discovered that dopamine (DA) is synthesized in the rat injured spinal cord and is involved in lower urinary tract (LUT) activity. To fully understand the role of spinal DAergic machinery in micturition, we examined urodynamic responses in female rats during pharmacological modulation of the DA pathway.

Superficial peroneal neuromodulation of persistent bladder underactivity induced by prolonged pudendal afferent nerve stimulation in cats.

The purpose of this study is to determine whether superficial peroneal nerve stimulation (SPNS) can reverse persistent bladder underactivity induced by prolonged pudendal nerve stimulation (PNS). In 16 α-chloralose-anesthetized cats, PNS and SPNS were applied by nerve cuff electrodes. Skin surface electrodes were also used for SPNS.

Model Analysis of Post-Stimulation Effect on Axonal Conduction and Block.

Objective: To reveal the possible contribution of changes in membrane ion concentration gradients and ion pump activity to axonal conduction/block induced by long-duration electrical stimulation.

Methods: A new model for conduction and block of unmyelinated axons based on the classical Hodgkin-Huxley (HH) equations is developed to include changes in Na and K concentrations and ion pumps. The effect of long-duration stimulation on axonal conduction/block is analyzed by computer simulation using this new model.

Prostate-Specific Deletion of Cdh1 Induces Murine Prostatic Inflammation and Bladder Overactivity.

Benign prostatic hyperplasia (BPH) is an age-related debilitating prostatic disease that is frequently associated with prostatic inflammation and bothersome lower urinary tract symptoms (LUTS). Animal models have shown that formalin- and bacterial-induced prostatic inflammation can induce bladder dysfunction; however, the underlying mechanisms contributing to prostatic inflammation in BPH and bladder dysfunction are not clear. We previously reported that E-cadherin expression in BPH is downregulated in hyperplastic nodules compared with expression in adjacent normal tissues.

Bladder underactivity induced by prolonged pudendal afferent activity in cats.

The purpose of this study was to determine the effects of pudendal nerve stimulation (PNS) on reflex bladder activity and develop an animal model of underactive bladder (UAB). In six anesthetized cats, a bladder catheter was inserted via the urethra to infuse saline and measure pressure. A cuff electrode was implanted on the pudendal nerve.