Role of Noradrenergic Pathways in Sneeze-induced Urethral Continence Reflex in Rats.
From: Dept. of Urology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA.
American journal of physiology. Renal physiology
- Publish Date: Feb 2007
- ISSN: 0363-6127
- Volume: 292
- Issue: 2
- Pages: F639-46
- Medium: Print
- Language: English
- Citation (JAMA): Kaiho Yasuhiro, Kamo Izumi, Chancellor Michael B, et al. Role of Noradrenergic Pathways in Sneeze-induced Urethral Continence Reflex in Rats.. Am. J. Physiol. Renal Physiol. Feb 2007;292:F639-46
Abstract
To clarify the role of noradrenergic pathways in preventing stress urinary incontinence (SUI) during sneezing, we investigated the effect of the norepinephrine reuptake inhibitor nisoxetine and alpha-adrenoceptor antagonists phentolamine (nonspecific blocker) and prazosin (alpha(1)-receptor-selective blocker) on the neurally evoked urethral continence reflex induced by sneezing in rats. The amplitude of urethral pressure responses during sneezing (A-URS), urethral baseline pressure (UBP) at the midurethra, and sneeze-induced leak point pressure (S-LPP) were measured in normal female adult rats and rats with SUI induced by vaginal distention (VD). In normal rats, intrathecal (it) phentolamine (0.02 nmol) and prazosin (0.02 nmol) decreased A-URS by 11.9 and 15.7%, respectively, without affecting UBP. In both normal and VD rats, intravenous (iv) application of nisoxetine (1 mg/kg) increased A-URS by 17.2 and 18.3% and UBP by 23.7 and 32.7%, respectively. Phentolamine or prazosin (both it) eliminated nisoxetine-induced increases in A-URS, but not the increases in UBP, which were, however, suppressed by iv phentolamine (5 mg/kg) or prazosin (1 mg/kg). Sneezing induced fluid leakage from the urethral orifice in VD rats, but not in normal rats. In VD rats, S-LPP was increased by 30.2% by iv nisoxetine. Application of phentolamine and prazosin (both it) decreased S-LPP by 15.7 and 20.6%, respectively, and nisoxetine induced increases in S-LPP to 13.2 and 12.3%, respectively. These results indicate that activation of the noradrenergic system by a norepinephrine reuptake inhibitor can prevent SUI via alpha(1-)adrenoceptors by enhancing the sneeze-induced active urethral closure mechanism at the spinal level and augmenting UBP at the periphery.
Mesh Headings (Keywords): Adrenergic Uptake Inhibitors, Adrenergic alpha-Antagonists, Animals, Female, Fluoxetine, Norepinephrine, Phentolamine, Prazosin, Pressure, Rats, Rats, Sprague-Dawley, Sneezing, Urethra, Urinary Incontinence, Stress, Vagina
Check for Full Text / PubMed Unique Identifier (PMID): 17047168
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