Effects of High Salt Intake on Detrusor Muscle Contraction in Dahl Salt-Sensitive Rats.

Ryoya Kawata,Kotomi Maeda,Yuji Hotta,Kazunori Kimura,Tomoya Kataoka

doi:10.3390/nu13020539

Ryoya Kawata, Kotomi Maeda + Show 3 more

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https://doi.org/10.3390/nu13020539

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Abstract

High salt intake has been reported as a risk factor for urinary storage symptoms. However, the association between high salt intake and detrusor muscle contraction is not clear. Therefore, we investigated the effects of high salt intake on the components of detrusor muscle contraction in rats. Six-week-old male Dahl salt-resistant (DR; n = 5) and Dahl salt-sensitive (DS; n = 5) rats were fed a high salt (8% NaCl) diet for one week. The contractile responses of the detrusor muscle to the cumulative administration of carbachol and electrical field stimulation (EFS) with and without suramin and atropine were evaluated via isometric tension study. The concentration–response curves of carbachol were shifted more to the left in the DS group than those in the DR group. Contractile responses to EFS were more enhanced in the DS group than those in the DR group (p < 0.05). Cholinergic component-induced responses were more enhanced in the DS group than those in the DR group (p < 0.05). High salt intake might cause urinary storage symptoms via abnormalities in detrusor muscle contraction and the enhancement of cholinergic signals. Excessive salt intake should be avoided to preserve bladder function.

Highlights

In modern aging societies, lower urinary tract symptoms (LUTS) are a serious public health concern [1]
LUTS refers to symptoms related to urination, which can be divided into urinary storage symptoms, voiding symptoms, and post-micturition symptoms [2]
We previously reported that one week of high salt intake in Dahl salt-sensitive (DS) rats was associated with the upregulation of epithelial sodium channel alpha expression and contributed to urinary frequency [12]

Summary

Introduction

Lower urinary tract symptoms (LUTS) are a serious public health concern [1]. As bladder dysfunction that leads to LUTS may have different causes, prevention and treatment methods that consider the patient’s underlying condition are needed [4]. Despite the availability of a range of treatment methods, including behavioral, pharmacological, and surgical approaches, many cases of LUTS are refractory [5,6,7]. Previous epidemiological studies reported that lifestyle habits such as overeating, smoking, and stress are associated with the development and progression of urinary storage symptoms, including urinary frequency and urgency [8,9,10]. A recent cross-sectional study conducted in Japan reported that high salt intake is one of the causes of urinary storage symptoms such as nocturia and nocturnal polyuria [11]

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