Effects of denervation on muscarinic receptors in the at bladder

Autor: J.F.B. Morrison, E. M. Whitaker, Alan J. Nimmo, K.T. Gunasena
Rok vydání: 1995
Předmět:
Zdroj: British Journal of Urology. 76:291-296
ISSN: 1464-410X
0007-1331
DOI: 10.1111/j.1464-410x.1995.tb07703.x
Popis: Objective To demonstrate the specific distribution of muscarinic receptors in the rat urinary bladder and to investigate the effects of afferent and efferent denervation on the density and distribution of muscarinic receptors. Materials and methods Urinary bladders were obtained from female rats which had been injected with vehicle (control), or neonatally with capsaicin (NC, afferent denervation) or which had their pelvic plexus removed (post-ganglionic denervation, PGD, efferent denervation). Tissue sections were used in radioligand-binding studies and for autoradiography with the muscarinic receptor ligand l-quinuclidinyl[phenyl-4–3H]benzilate (QNB). Results Binding of QNB was saturable and specific to a single population of binding sites, with a mean dissociation constant (Kd) of 1.05 ± 0.14 nm in controls and 0.90 ± 0.13 nm in rats with PGD. Post-ganglionic denervation caused a 37% increase in maximal binding (Bmax) of QNB from 437.1 ± 39.1 fmol/mg protein (control group) to 599.1 ± 4.5 fmol/mg protein (P < 0.02). Autoradiograms revealed muscarinic binding sites over the smooth muscle, but none over the epithelium. Smooth muscle binding sites were doubled after PGD but were unchanged after NC treatment. Conclusion Muscarinic receptors were localized over the smooth muscle of the rat bladder and were increased after post-ganglionic denervation. This increase may be responsible for the increased sensitivity to muscarinic agonists reported to occur after bladder denervation.
Databáze: OpenAIRE
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