Reflexes involving the external urethral sphincter in the cat

Garry, R. C.; Roberts, T. D. M.; Todd, J. K.

doi:10.1113/jphysiol.1959.sp006366

Cited by 159 publications

(56 citation statements)

References 12 publications

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“…The presence of tonic PAD also suggests the existence of tonically active interneurones in decerebrate preparations. Figure 5 shows (Garry, Roberts & Todd, 1959 (Schmidt, 1971). As Fig.…”

Section: Pad Of Perineal Afferents During Micturitionmentioning

confidence: 99%

Primary afferent depolarization of cat pudendal afferents during micturition and segmental afferent stimulation.

Angel¹,

Fyda²,

McCrea³

et al. 1994

The Journal of Physiology

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1. This investigation examined primary afferent depolarization (PAD) of perineal afferents during micturition and evoked by electrical stimulation of perineal, hindlimb cutaneous and muscle-nerves. PAD was inferred from changes in excitability of spinal terminals of single afferents in decerebrate and chloralose-anaesthetized paralysed male cats. Observations were made on perineal afferent fibres travelling in the sensory branch of the pudendal (SPud) and superficial perineal (SPeri) nerves.2. Micturition was evoked by distension of the bladder and excitability changes were measured in twenty-seven SPud afferents. In ten afferents, there was evidence of PAD during micturition. The time course of PAD was similar to the period of decreased activity in sphincter muscle efferents during micturition. In four afferents, there was decreased excitability during voiding that was interpreted as removal of tonic PAD. In the remaining thirteen afferents there were no detectable changes in excitability.Bladder distension in the absence of micturition failed to change the excitability of any SPud afferents tested. 3. Almost all SPud afferents were subject to PAD upon stimulation of cutaneous nerves.Superficial perineal, long saphenous, caudal cutaneous sural and the predominantly cutaneous posterior tibial nerves were particularly effective in evoking PAD. While group I strength stimulation of hindlimb muscle-nerves produced PAD of some SPud fibres, group II stimulation often increased the magnitude or incidence of PAD. The patterns and magnitude of PAD observed in SPeri afferents were similar to those observed in SPud afferents.4. Since some SPud afferents were subject to PAD during micturition, PAD is prpbably one mechanism responsible for suppression of sphincter reflexes during niicturition.Additional roles of PAD of perineal afferents evoked by activation of hindlimb cutaneous and muscle afferents are discussed.

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“…The presence of tonic PAD also suggests the existence of tonically active interneurones in decerebrate preparations. Figure 5 shows (Garry, Roberts & Todd, 1959 (Schmidt, 1971). As Fig.…”

Section: Pad Of Perineal Afferents During Micturitionmentioning

confidence: 99%

Primary afferent depolarization of cat pudendal afferents during micturition and segmental afferent stimulation.

Angel¹,

Fyda²,

McCrea³

et al. 1994

The Journal of Physiology

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“…The reflexes that are initiated by visceral distension or contraction and are retained after a low lumbar spinal transaction include the sphincteric reflexes and reflexes affecting the somatic musculature (Bishop, Garry, Roberts & Todd, 1956;Garry, Roberts & Todd, 1959;McPherson, 1966;Evans & McPherson, 1958). The latencies of pelvic-pudendal nerve reflexes are the shortest of all reflexes evoked from pelvic nerve afferents (Bradley & Teague, 1977;Floyd, McMahon & Morrison, 1979), and hypogastric afferents appear not to have any action on pudendal nerve efferents (unpublished observations).…”

Section: Reflex Pathways That May Be Mediated By Group a Interneuronesmentioning

confidence: 99%

Two groups of spinal interneurones that respond to stimulation of the abdominal viscera of the cat

McMahon

Morrison

1982

The Journal of Physiology

114

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SUMMARY1. Recordings have been made from sixty-three spinal interneurones that received inputs from the abdominal viscera. These were divided into two groups: group A were sacral interneurones without either significant ascending projections or afferent input from the lumbar splanchnic nerves and group B were neurones with short ascending axons and afferent inputs from the lumbar splanchnic nerves, and often also from the pelvic and pudendal nerves.2. Somato-visceral convergence was common in both groups, and the somatic receptive fields of group A interneurones were in muscle and joints and less commonly skin innervated by sacral segments, whereas those of group B were innervated by lumbar and sacral segments.3. Within both groups of neurones there was a proportion that showed no response to distension or contractions of the viscera, (despite the fact that they responded to visceral nerve stimulation), and those which did respond showed graded changes in discharge rate as intravesical pressure was raised. Some cells received inputs from only one viscus: the receptive fields of these cells are described as simple and the effect of raising the pressure in that viscus was either to excite or to inhibit the central neurone. Other cells received convergent inputs from two viscera: their receptive fields are described as compound and the effect of raising intraluminal pressures in the viscera allowed a further subdivision of these cells into two types. Type I cells were either excited or inhibited by distension or contractions of either viscus. Type II cells were excited by natural stimulation of one of the innervated viscera but inhibited by similar changes in the other. The static pressure thresholds of these cells were 9+5 mmHg intravesical pressure, and 24+11 mmHg intracolonic pressure (means + S.D.).4. It is proposed that within the population of neurones described there are cells (group A interneurones) that either mediate the vesico-and colono-sphincteric reflexes or the colono-vesical interactions that can be seen in the micturition reflex pathway.5. It is proposed that the group B interneurones with short ascending projections mediate the vesico-and colono-sympathetic reflexes because their patterns of convergence, position in the spinal cord, latencies, and static pressure thresholds are consistent with those reflexes.

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“…Fluid flow in the urethra evokes firing in pudendal afferents innervating the urethra in cats (Talaat 1937, Todd 1964 and rats (Le Feber et al 1998), and this sensory signal augments the amplitude of ongoing bladder contractions in cats (Barrington 1931, 1941, Garry et al 1959 and increases the frequency of isometric bladder contractions in rats (Jung et al 1999). Similarly, electrical stimulation of the urethral sensory branch of the pudendal nerve in cats leads to excitation of the bladder (Mazieres et al 1997, Jiang andLindström 1999), inhibition of the external urethral sphincter, and voiding (Shefchyk and Buss 1998).…”

Section: Introductionmentioning

confidence: 99%

Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

et al. 2008

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Urinary retention is the inability to empty the bladder completely, and may result from bladder hypocontractility, increases in outlet resistance, or both. Chronic urinary retention can lead to several urological complications and is often refractory to pharmacologic, behavioral, and surgical treatments. We sought to determine whether electrical stimulation of sensory fibers in the pudendal nerve could engage an augmenting reflex and thereby improve bladder emptying in an animal model of urinary retention. We measured the efficiency of bladder emptying with and without concomitant electrical stimulation of pudendal nerve afferents in urethane anesthetized rats. Voiding efficiency (VE=voided volume/initial volume) was reduced from 72±7% to 29±7% following unilateral transection of the sensory branch of the pudendal nerve (UST) and from 70±5% to 18±4% following bilateral transection (BST). Unilateral electrical stimulation of the proximal transected sensory pudendal nerve during distention-evoked voiding contractions significantly improved VE. Low intensity stimulation at frequencies of 1-50 Hz increased VE to 40-51% following UST and to 39-49% following BST, while high intensity stimulation was ineffective at increasing VE. The increase in VE was mediated by increases in the duration of distention-evoked voiding bladder contractions, rather than increases in contraction amplitude. These results are consistent with an essential role for pudendal sensory feedback in efficient bladder emptying, and raise the possibility that electrical activation of pudendal nerve afferents may provide a new approach to restore efficient bladder emptying in persons with urinary retention.

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Reflexes involving the external urethral sphincter in the cat

Cited by 159 publications

References 12 publications

Primary afferent depolarization of cat pudendal afferents during micturition and segmental afferent stimulation.

Primary afferent depolarization of cat pudendal afferents during micturition and segmental afferent stimulation.

Two groups of spinal interneurones that respond to stimulation of the abdominal viscera of the cat

Improved bladder emptying in urinary retention by electrical stimulation of pudendal afferents

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