Serotonergic modulation of spinal ascending activity and sacral reflex activity evoked by pelvic nerve stimulation in cats

Espey, Mary Jane; Du, Huan-Ji; Downie, John W.

doi:10.1016/s0006-8993(98)00401-6

Cited by 78 publications

(42 citation statements)

References 41 publications

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“…A portion of the supraspinal-descending control innervates the DL directly (Ding et al, 1995;Hermann et al, 1998). We therefore evaluated the supraspinal terminations around the EUS-innervating motoneurons in this area using serotonin immunoreactivity, because brainstem serotonergic pathways are involved in the control of micturition (McMahon and Spillane, 1982;Durant and Yaksh, 1988;Fukuda and Koga, 1991;Thor and Katofiasc, 1995;Espey et al, 1998).…”

Section: Relationship Between Detrusor-eus Coordination and Preservatmentioning

confidence: 99%

Coordination of the Bladder Detrusor and the External Urethral Sphincter in a Rat Model of Spinal Cord Injury: Effect of Injury Severity

Pikov¹,

Wrathall

2001

J. Neurosci.

105

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Recovery of urinary tract function after spinal cord injury (SCI) is important in its own right and may also serve as a model for studying mechanisms of functional recovery after injury in the CNS. Normal micturition requires coordinated activation of smooth muscle of the bladder (detrusor) and striated muscle of the external urethral sphincter (EUS) that is controlled by spinal and supraspinal circuitry. We used a clinically relevant rat model of thoracic spinal cord contusion injury to examine the effect of varying the degree of residual supraspinal connections on chronic detrusor-EUS coordination. Urodynamic evaluation at 8 weeks after SCI showed that detrusor contractions of the bladder recovered similarly in groups of rats injured with a 10 gm weight dropped 12.5, 25, or 50 mm onto the spinal cord. In contrast, the degree of coordinated activation of the EUS varied with the severity of initial injury and the degree of preservation of white matter at the injury site. The 12.5 mm SCI resulted in the sparing of 20% of the white matter at the injury site and complete recovery of detrusor-EUS coordination. In more severely injured rats, the chronic recovery of detrusor-EUS coordination was very incomplete and correlated to decreased innervation of lower motoneurons by descending control pathways and their increased levels of mRNA for glutamate receptor subunits NR2A and GluR2. These results show that the extent of recovery of detrusor-EUS coordination depends on injury severity and the degree of residual connections with brainstem control centers.

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Section: Relationship Between Detrusor-eus Coordination and Preservatmentioning

confidence: 99%

Coordination of the Bladder Detrusor and the External Urethral Sphincter in a Rat Model of Spinal Cord Injury: Effect of Injury Severity

Pikov¹,

Wrathall

2001

J. Neurosci.

105

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“…These effects are blocked by mesulergine, a 5-HT 2 receptor antagonist (247,588). Intrathecal administration of methysergide, a 5-HT 1/2 antagonist, or zatosetron, a 5-HT 3 antagonist, decreases the micturition volume threshold in cats (206), implying that descending serotonergic pathways tonically depress the afferent limb of the micturition reflex through 5HT 2 and/or 5HT 3 receptors.…”

Section: Neurotransmitters In Central Pathways Controlling Micturitionmentioning

confidence: 99%

“…The sympathetic autonomic nuclei as well as the sphincter motor nuclei also receive a serotonergic input from the raphe nucleus (153,206,634). Serotonergic activity mediated via 5-HT 2 and 5-HT 3 receptors enhances urine storage by facilitating sphincter reflexes in cats (139,206).…”

Section: Neurotransmitters In Central Pathways Controlling Micturitionmentioning

confidence: 99%

“…Serotonergic activity mediated via 5-HT 2 and 5-HT 3 receptors enhances urine storage by facilitating sphincter reflexes in cats (139,206). A recent study in rats also reported that activation of 5HT 2C receptors enhances the urethral closure reflex induced by pudendal nerve-mediated urethral striated muscle contraction during sneezing at the spinal level whereas 5HT 1A receptors inhibit it because intrathecally applied 8-OH-DPAT (a 5HT 1A agonist) decreases urethral contractile responses during sneezing and mCPP (a 5HT 2 agonist) increases them, and the effects of 8-OH-DPAT and mCPP are antagonized by intrathecal applications of WAY-100635, a selective 5HT 1A antagonist, and RS-102221, a selective 5HT 2C antagonist, respectively (432).…”

Section: Neurotransmitters In Central Pathways Controlling Micturitionmentioning

confidence: 99%

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Neural Control of the Lower Urinary Tract

1997

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This article summarizes anatomical, neurophysiological, pharmacological, and brain imaging studies in humans and animals that have provided insights into the neural circuitry and neurotransmitter mechanisms controlling the lower urinary tract. The functions of the lower urinary tract to store and periodically eliminate urine are regulated by a complex neural control system in the brain, spinal cord, and peripheral autonomic ganglia that coordinates the activity of smooth and striated muscles of the bladder and urethral outlet. The neural control of micturition is organized as a hierarchical system in which spinal storage mechanisms are in turn regulated by circuitry in the rostral brain stem that initiates reflex voiding. Input from the forebrain triggers voluntary voiding by modulating the brain stem circuitry. Many neural circuits controlling the lower urinary tract exhibit switch-like patterns of activity that turn on and off in an all-or-none manner. The major component of the micturition switching circuit is a spinobulbospinal parasympathetic reflex pathway that has essential connections in the periaqueductal gray and pontine micturition center. A computer model of this circuit that mimics the switching functions of the bladder and urethra at the onset of micturition is described. Micturition occurs involuntarily in infants and young children until the age of 3 to 5 years, after which it is regulated voluntarily. Diseases or injuries of the nervous system in adults can cause the re-emergence of involuntary micturition, leading to urinary incontinence. Neuroplasticity underlying these developmental and pathological changes in voiding function is discussed.

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“…Methysergide 100 µmol/l (non-selective 5-HT 1 and 5-HT 2 receptor antagonist) [25], ketanserin 1 µmol/l (selective 5HT 2 receptor antasonist), ondansetron 1 µmol/l (selective 5HT 3 receptor antagonist), and GR113808 10 µmol/l (selective 5HT 4 receptor antagonist) were given for 15 min before each set of experiment (fig. 3).…”

Section: Resultsmentioning

confidence: 99%

Signal Transduction Underlying the Inhibitory Mechanism of Fluoxetine on Electrical Field Stimulation Response in Rat Ileal Smooth Muscle

Khin

Zaw²,

Sohn³

2017

Pharmacology

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Fluoxetine (FLX), a well-known antidepressant drug under the class of selective serotonin reuptake inhibitor, exerts its action by inhibiting the reuptake of serotonin selectively. In some studies, it has been demonstrated that FLX relaxes the intestinal smooth muscle. In this study, we aimed at studying the signal transduction pathway underlying the muscle relaxation effect of FLX on electrically stimulated rat ileal muscle contraction. To investigate the possible mechanism involved, various antagonists were used. It was found that inhibition with L-N^G-nitroarginine methyl ester, ondansetron, GR113808 and bicuculline enhanced the relaxation effect of FLX. However, the effect of FLX was nullified under the presence of atropine, calcium channel modulator (calcium ionophore A23187), and potassium channel blockers (tetraethylammonium chloride, 4-aminopyridine and glybenclamide). Specific pathway-inhibiting antagonists, Y27632 (Rho-kinase inhibitor) and U73122 (phospholipase-C inhibitor) reversed the antagonistic effect of FLX, while ML-9 (myosin light chain kinase inhibitor) and chelerythrine (protein kinase C inhibitor) augmented the FLX-induced inhibition effect. Taken together, we concluded that FLX exerts the inhibitory effect on electric field stimulation response in rat ileal smooth muscle by the inhibition of muscarinic receptors, decrease of intracellular calcium level by inhibiting phospholipase C and opens the potassium channels.

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Serotonergic modulation of spinal ascending activity and sacral reflex activity evoked by pelvic nerve stimulation in cats

Cited by 78 publications

References 41 publications

Coordination of the Bladder Detrusor and the External Urethral Sphincter in a Rat Model of Spinal Cord Injury: Effect of Injury Severity

Coordination of the Bladder Detrusor and the External Urethral Sphincter in a Rat Model of Spinal Cord Injury: Effect of Injury Severity

Neural Control of the Lower Urinary Tract

Signal Transduction Underlying the Inhibitory Mechanism of Fluoxetine on Electrical Field Stimulation Response in Rat Ileal Smooth Muscle

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