Related Experiment Videos
[Autoradiographic localization of muscarinic receptors in diabetic rat bladder]
M Saito1, I Nakamura, I Miyagawa
1Department of Urology, Tottori University School of Medicine.
Purpose:
We evaluated the alterations of density, localization and subtype specificity of muscarinic receptors in experimentally-induced diabetic rat bladder.
Methods:
Five groups of rats were maintained for sixteen weeks 1) diabetic, 2) diabetic insulin-treated (insulin started 8 weeks after the onset of diabetes), 3) sucrose-fed diuretic, 4) sucrose-removed and 5) age matched controls. We used radioligand binding technique and light microscopic autoradiography to define the density and distribution of muscarinic receptors in the rat urinary bladder.
Results & Conclusion:
Saturation experiments showed an increase in the density of muscarinic receptors in the bladders of diabetic and diuretic rats compared with age matched controls. Insulin treatment partially reversed the up-regulatin of muscarinic receptors in rat urinary bladder. Autoradiographic studies also indicated that muscarinic receptors were located in all layers of the bladder muscularis. The muscularis of the bladder dome contained higher densities of muscarinic receptors than that of the bladder base. Lack of [3H]QNB binding to transitional epithelium, lamina propria, and tunica adventitia suggests an absence of muscarinic receptors in these regions. Inhibition of [3H]QNB binding to the bladder sections by selective muscarinic antagonists indicated existence of the M2 and M3 receptor subtypes in the muscularis of the rat bladder.
Insights
Diabetes increases muscarinic receptors in rat bladders, particularly in the muscularis layer. Insulin treatment partially reverses this upregulation, suggesting a therapeutic target for diabetic bladder dysfunction.
Area of Science:
- Pharmacology
- Urology
- Endocrinology
Context:
- Diabetic complications affect the urinary system.
- Muscarinic receptors play a role in bladder function.
- Understanding receptor changes in diabetes is crucial for treatment.
Purpose:
- To investigate changes in muscarinic receptor density, localization, and subtype specificity in a rat model of diabetes.
- To evaluate the effect of insulin treatment on these receptor alterations.
Summary:
- Diabetic and diuretic rats showed increased muscarinic receptor density in bladder tissue compared to controls.
- Insulin therapy partially reversed this increase.
- Muscarinic receptors (M2 and M3 subtypes) were localized to the bladder muscularis, with higher density in the dome than the base.
Impact:
- Findings suggest muscarinic receptor upregulation in diabetic bladders.
- Potential therapeutic implications for managing diabetic bladder dysfunction.
- Highlights the role of M2 and M3 receptors in the bladder wall.