Adrenergic influences on the voiding cycle in the decerebrated dog

Nishizawa, Osamu; Fukuda, Takashi; Matsuzaki, Akinobu; Moriya, Itaru; Satoh, Sadamoto; Tsuchida, Seigi

doi:10.1002/nau.1930050507

Cited by 5 publications

(5 citation statements)

References 19 publications

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“…Bilateral hypogastric nerve transection was used as an alternate, nonselective means of blocking the sympathetic bladder innervation, and results were similar under surgical and pharmacological block. Hypogastric nerve transection decreased the DTV, consistent with previous findings (31,35,50) and also decreased the STV. Additionally, the decrease in volume thresholds was consistent with the volume threshold changes induced by ␤-block but contrary to the changes due to ␣-block, suggesting that the ␤-adrenergic pathway has greater influence over the micturition threshold than the ␣-adrenergic pathway.…”

Section: Discussionsupporting

confidence: 91%

“…Blocking the ␤-adrenergic bladder pathway with propranolol reduced volume thresholds but did not affect the magnitude of the electrically evoked bladder contraction. The reduction in distension-evoked volume threshold corroborates previous studies in the dog (35) and cat (16), both of which express ␤ 1 -and ␤ 2 -receptor subtypes (1,33,34). However, propranolol did not alter the micturition thresholds in the rat (31), which expresses the ␤ 3 -receptor subtype (15,47), underscoring both important species differences as well as the substantially higher affinity of propranolol for ␤ 1 -and ␤ 2 -receptor subtypes (21).…”

Section: Discussionsupporting

confidence: 91%

“…Although similar increases in the micturition volume threshold following ␣-adrenergic block were reported in the decerebrate dog (35) and conscious rat (43), others have reported decreases in the micturition volume threshold in cats (16,18). One factor potentially responsible for these differences is peripheral (35,43) vs. central (18) drug administration (25). As well, the results may reflect variation in the ␣-adrenergic receptor subtypes, as intrathecal injection of prazosin increased the micturition volume threshold in rats (25) but had little effect in cats (18).…”

Section: Discussionsupporting

confidence: 73%

“…Blocking the ␣-adrenergic pathway with phentolamine increased the threshold volumes for distention-evoked and stimulation-evoked contractions. Although similar increases in the micturition volume threshold following ␣-adrenergic block were reported in the decerebrate dog (35) and conscious rat (43), others have reported decreases in the micturition volume threshold in cats (16,18). One factor potentially responsible for these differences is peripheral (35,43) vs. central (18) drug administration (25).…”

Section: Discussionmentioning

confidence: 62%

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Mechanisms of reflex bladder activation by pudendal afferents

Woock

Yoo

Grill

2011

American Journal of Physiology-Regulatory, Integrative and Comp

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Activation of pudendal afferents can evoke bladder contraction or relaxation dependent on the frequency of stimulation, but the mechanisms of reflex bladder excitation evoked by pudendal afferent stimulation are unknown. The objective of this study was to determine the contributions of sympathetic and parasympathetic mechanisms to bladder contractions evoked by stimulation of the dorsal nerve of the penis (DNP) in ␣-chloralose anesthetized adult male cats. Bladder contractions were evoked by DNP stimulation only above a bladder volume threshold equal to 73 Ϯ 12% of the distension-evoked reflex contraction volume threshold. Bilateral hypogastric nerve transection (to eliminate sympathetic innervation of the bladder) or administration of propranolol (a ␤-adrenergic antagonist) decreased the stimulation-evoked and distensionevoked volume thresholds by Ϫ25% to Ϫ39%. Neither hypogastric nerve transection nor propranolol affected contraction magnitude, and robust bladder contractions were still evoked by stimulation at volume thresholds below the distension-evoked volume threshold. As well, inhibition of distention-evoked reflex bladder contractions by 10 Hz stimulation of the DNP was preserved following bilateral hypogastric nerve transection. Administration of phentolamine (an ␣-adrenergic antagonist) increased stimulation-evoked and distension-evoked volume thresholds by 18%, but again, robust contractions were still evoked by stimulation at volumes below the distension-evoked threshold. These results indicate that sympathetic mechanisms contribute to establishing the volume dependence of reflex contractions but are not critical to the excitatory pudendal to bladder reflex. A strong correlation between the magnitude of stimulation-evoked bladder contractions and bladder volume supports that convergence of pelvic afferents and pudendal afferents is responsible for bladder excitation evoked by pudendal afferents. Further, abolition of stimulationevoked bladder contractions following administration of hexamethonium bromide confirmed that contractions were generated by pelvic efferent activation via the pelvic ganglion. These findings indicate that pudendal afferent stimulation evokes bladder contractions through convergence with pelvic afferents to increase pelvic efferent activity.cat; micturition; parasympathetic; sympathetic DEPENDING ON THE STIMULATION frequency, electrical stimulation of pudendal afferents evokes spinal reflexes that either inhibit the bladder and promote continence or excite the bladder and cause micturition in both cats (5,6,41,45,49) and persons with spinal cord injury (48). Previous results suggest that bladder inhibition by pudendal afferent stimulation arises from activation of hypogastric efferents and subsequent synaptic and ganglionic inhibition of parasympathetic efferents (8, 30), but the mechanisms of bladder excitation by pudendal afferent stimulation are not known. Contraction of the bladder by pudendal afferent stimulation may result from activation of a vestigial reflex from perig...

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Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 91%

Section: Discussionsupporting

confidence: 73%

Section: Discussionmentioning

confidence: 62%

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Mechanisms of reflex bladder activation by pudendal afferents

Woock

Yoo

Grill

2011

American Journal of Physiology-Regulatory, Integrative and Comp

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“…Mongrel dogs were decerebrated at the supracollicular level through craniotomy after ligation of the bilateral carotid arteries in order to create reflex micturition in response to bladder filling (Nishizawa et al 1986). The bladder was filled via one channel of the suprapubic double lumen catheter with physiological saline, while bladder pressure was measured via the other channel connected to a Statham P50 transducer.…”

mentioning

confidence: 99%

Pontine urine storage center in the dog.

Nishizawa

Sugaya

Noto

et al. 1987

Tohoku J. Exp. Med.

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Electrical stimulation of the presumptive pontine urine storage center, areas ventral to and/or lateral to the pontine micturition center, elicited an increase in threshold volume at which reflex micturition occurred in response to bladder filling with physiological saline, suggesting a facilitatory effect on the urine storage function.The electrolytic lesions made in the stimulated areas were histologically identified to distribute at the nucleus reticularis pontis oralis, Kolliker-Fuse nucleus and subcoeruleus.These nucleus seemed to work as a

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Effect of oxybutynin on reflex micturition in the decerebrate dog as determined by urodynamic evaluation

Nishizawa

Sugaya

Kohama

et al. 1989

Neurourology and Urodynamics

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The effect of oxybutynin on reflex micturition in the decerebrate dog was investigated by cystometric and striated urethral sphincter EMG studies. Reflex micturition consisting of bladder contraction and relaxation of the striated urethral sphincter occurred when a critical degree of filling was reached in the absence and presence of cumulative doses of 30, 100, and 300 pgikg of oxybutynin. Oxybutynin at doses of 30, 100, and 300 pg/kg produced a significant increase in threshold volume during the collecting phase in a dose-dependent manner. In the urodynamic parameters of the emptying phase considered to be influenced greatly by cholinergic activity there was a small but significant decrease in the maximum bladder pressure only at a dose of 300 pg/kg. The present study supports urodynamically clinical usefulness of oxybutynin for the relief of symptoms associated with detrusor instability and hyperreflexia.

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Adrenergic influences on the voiding cycle in the decerebrated dog

Cited by 5 publications

References 19 publications

Mechanisms of reflex bladder activation by pudendal afferents

Mechanisms of reflex bladder activation by pudendal afferents

Pontine urine storage center in the dog.

Effect of oxybutynin on reflex micturition in the decerebrate dog as determined by urodynamic evaluation

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