Narendra Bhadra

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A reversible electrical block of the pudendal nerves may provide a valuable method for restoration of urinary voiding in individuals with bladder-sphincter dyssynergia. This study quantified the stimulus parameters and effectiveness of high frequency (HFAC) sinusoidal waveforms on the pudendal nerves to produce block of the external urethral sphincter(More)
AIMS Reflex bladder excitation has been demonstrated by stimulation of the pudendal nerve and several of its distal branches. However, excitation parameters have not been consistent and the relationship to anatomical locations within the urethra has not been fully investigated. An improved understanding of the lower urinary tract neurophysiology will(More)
We evaluated variable patterns of pudendal nerve (PN) stimuli for reflex bladder excitation. Reflex activation of the bladder has been demonstrated previously with 20-33 Hz continuous stimulation of PN afferents. Neuronal circuits accessed by afferent mediated pathways may respond better to physiological patterned stimuli than continuous stimulation.(More)
Experiments were conducted to measure the bladder and urethral pressures evoked by intraspinal microstimulation of the sacral segments (S1-S2) in neurologically intact, chloralose anesthetized adult male cats. The bladder pressure was measured with a superpubic catheter and the urethral pressure was measured simultaneously at the level of the urethral(More)
Anatomical and histological methods were combined with measurements of the urethral pressure profile (UPP) to investigate the functional aspects of the urethra in male cats. A silicone rubber catheter with two microdiaphragm pressure transducers was used to measure the UPP. Gross anatomy and ultrastructure of the urethra at each segment were examined and(More)
Electrical stimulation of the sacral anterior roots using conventional rectangular current pulses results in a simultaneous contraction of the urinary bladder and the striated urethral sphincter. Using a tripolar nerve cuff electrode with quasitrapezoidal current pulses and appropriate stimulation parameters, hyperpolarization of the nerve-fiber cell(More)
Reflex bladder excitation has been evoked via pudendal nerve, pudendal nerve branch and intraurethral stimulation; however, afferent-evoked bladder emptying has been less efficient than direct activation of the bladder via sacral root stimulation. A stimulation method that improves activation of the urethra-bladder excitatory reflex with minimal sphincter(More)
The purpose of this work was to electrically activate small-diameter motor fibers in the sacral anterior roots innervating the urinary bladder, without activating the large-diameter fibers to the sphincter. Quasitrapezoidal current pulses were applied through tripolar spiral nerve electrodes on selected anterior sacral roots during acute experiments on(More)
AIM We investigated the efficacy of selective activation of the smaller diameter axons in the sacral anterior roots for electrically induced bladder voiding. MATERIALS AND METHODS Acute experiments were conducted in five adult dogs. The anterior sacral roots S2 and S3 were implanted bilaterally with tripolar electrodes. Pressures were recorded from the(More)
Nerve cuff electrodes are a principle tool of basic and applied electro-neurophysiology studies and are championed for their ability to achieve good nerve recruitment with low thresholds. We describe the design and method of fabrication for a novel circumpolar peripheral nerve electrode for acute experimental use. This cylindrical cuff-style electrode(More)