Effect of neocuproine, a copper(i) chelator, on rat bladder function

Area of Science:

• Urology
• Neuropharmacology
• Physiology

Background:

• Nonadrenergic-noncholinergic (NANC) neurotransmission regulates bladder function.
• Copper ions play a role in neurotransmission, but their specific involvement in bladder NANC mechanisms is not fully understood.

Purpose of the Study:

• To investigate the role of copper(I) and copper(II) in regulating NANC neurotransmission in the rat urinary bladder.
• To determine the effects of neocuproine (NC) and cuprizone on nerve-evoked bladder contractions and voiding function.

Main Methods:

• Rat bladder strips were used to measure nerve-evoked contractions following electrical field stimulation.
• Cholinergic and adrenergic pathways were blocked using atropine and guanethidine.
• Voiding function was assessed in anesthetized rats using continuous infusion cystometry.
• Effects of neocuproine (NC), cuprizone, NC-copper(I) complex (NC-Cu), and suramin were evaluated.

Main Results:

• Neocuproine (NC) significantly enhanced transient, suramin-sensitive nerve-evoked bladder contractions, indicating facilitation of purinergic responses.
• NC also affected sustained contractions and basal tone, with effects dependent on concentration and presence of copper.
• Intravesical NC infusion decreased the intercontraction interval (ICI) in vivo, an effect blocked by suramin, suggesting enhanced bladder activity.
• Cuprizone and NC-Cu did not elicit similar effects, highlighting the specificity of copper(I) chelation.

Conclusions:

• Copper(I)-sensitive mechanisms tonically inhibit purinergic transmission in the urinary bladder.
• Neocuproine (NC) enhances bladder activity by facilitating purinergic excitatory responses.
• These findings suggest a novel regulatory role for copper in bladder NANC neurotransmission.