Detrusor-sphincteric dyssynergia in humans with spinal cord lesions may be caused by a loss of stable phase relations between and within oscillatory firing neuronal networks of the sacral micturition center

• Published in: Journal of the autonomic nervous system 1995-04, Vol.52 (2), p.181-202
• Main Authors: Schalow, G., Bersch, U., Michel, D., Koch, H.G.
• Format: Article
• Language: English
• Subjects: Action Potentials - physiology; Adult; Bladder dyssynergia; Brain Death; Cholinergic Fibers - physiology; Electrophysiology; Female; Humans; Interspike interval; Male; Mechanoreceptors - physiology; Motor Neurons - physiology; Motor Neurons, Gamma - physiology; Muscle Contraction - physiology; Muscle Spindles - physiology; Muscle, Smooth - innervation; Muscle, Smooth - physiopathology; Nerve Net - physiology; Oscillatory firing; Phase relation; Single-fibre action potential; Space life sciences; Spinal Cord - physiopathology; Spinal Cord Injuries - physiopathology; Spinal cord lesion; Urinary Bladder - innervation; Urinary Bladder - physiopathology; Urodynamics - physiology
• ISSN: 0165-1838; 1872-7476
• DOI: 10.1016/0165-1838(94)00155-D

(1) Single-fibre action potentials (APs) were recorded with 2 pairs of wire electrodes from lower sacral nerve roots during surgery in patients with spinal cord lesions and in a brain-dead human. Conduction velocity distribution histograms were constructed for afferent and efferent fibres, nerve fibre groups were identified and simultaneous impulse patterns of α and γ-motoneurons and secondary muscle spindle afferents (SP2) were constructed. Temporal relations between afferent and efferent APs were analysed by interspike interval (II) and phase relation changes. (2) In a paraplegic with hyperreflexia of the bladder, urinary bladder stretch (S1) and tension receptor afferents (ST) fired already when the bladder was empty, and showed a several times higher bladder afferent activity increase upon retrograde bladder filling than observed in the brain-dead individual. Two α 2-motoneurons (FR) innervating the external bladder sphincter were already oscillatory firing to generate high activity levels when the bladder was empty. They showed activity levels with no bladder filling, comparable to those measured at a bladder filling of 600 ml in the brain-dead individual. A bladder storage volume of 600 ml was thus lost in the paraplegic, due to a too high bladder afferent input to the sacral micturition center, secondary to inflammation and hypertrophy of the detrusor. (3) In a brain-dead human, 2 phase relations existed per oscillation period of 160 ms between the APs of a sphincteric oscillatory firing α 2-motoneuron, a dynamic fusimotor and a secondary muscle spindle afferent fibre. Following stimulation of mainly somatic afferent fibres, the phase relations changed only little. (4) In a paraplegic with dyssynergia of the urinary bladder also 2 phase relations existed per oscillation period of 110 ms in a functional unit between the APs of a sphincteric α-motoneuron, a fusimotor and a secondary spindle afferent fibre. The phase relations changed with time following stimulation of mainly somatic afferents. A second functional unit organized by phase-related interactions was phase related to the first functional unit. (5) Following painful bladder catheter pulling, the parasympathetic division was transiently activated several times in the paraplegic. At times of activation of the parasympathetic division, 3 broad phase relations occurred within and between the two functional units, indicating that the parasympathetic division in the sacral micturition and defecati