Korean J Anat.  2008 Mar;41(1):67-72.

Distribution of Purinergic Receptor and Vanilloid Receptor Participating in Micturition and Reciprocal Relationship between Them

• Yang HJ
• Gil YC
• Lee HY

Abstract

Two of the synaptic receptors involved in the regulation of micturition, P2X(3) receptor, which is operated by ATP, and vanilloid receptor 1 (VR1), which is operated by capsaicin, are regarded as newcomers. To investigate the possibility that these receptors act as therapeutic targets for treatment of an overactive bladder, we investigated their distribution and reciprocal relationship. Eight-week-old Sprague Dawley rats were injected with retrograde nerve tracer within the bladder wall, and 15 rats were injected with 0.5% acetic acid inside the bladder. After a week, the animals were killed, and their dorsal root ganglia (DRG) at the levels of L6 and S1 were harvested. Immunohistochemistry or Western blot analysis of P2X(3) and VR1 were performed on the DRG. The DRG neurons with afferent fibers from the bladder had increased expression of VR1 and downregulated P2X(3) receptors. The P2X(3) receptor and VR1 seemed to account for the important parts of the hypersensitivity of the inflammatory bladder. We conclude that the simultaneous modulations of both P2X(3) receptor and VR1 may have a synergic effect on the treatment of overactive bladder and may produce greater response rates.

Keyword

Micturition; Bladder; P2X(3) receptor; VR1; Retrograde nerve tracing

MeSH Terms

Acetic Acid
Adenosine Triphosphate
Animals
Blotting, Western
Capsaicin
Diagnosis-Related Groups
Ganglia, Spinal
Hypersensitivity
Immunohistochemistry
Neurons
Rats
Rats, Sprague-Dawley
Receptors, Neurotransmitter
Urinary Bladder
Urinary Bladder, Overactive
Urination
Acetic Acid
Adenosine Triphosphate
Capsaicin
Receptors, Neurotransmitter