Selective inhibitory effect of imidafenacin and 5-hydroxymethyl tolterodine on capsaicin sensitive C fibers of the primary bladder mechanosensitive afferent nerves in the rat.
J Urol
; 193(4): 1423-32, 2015 Apr.
Article
em En
| MEDLINE
| ID: mdl-25219701
ABSTRACT
PURPOSE:
Imidafenacin and fesoterodine are used to treat overactive bladder. Imidafenacin, fesoterodine and its active metabolite 5-hydroxymethyl tolterodine are muscarinic receptor antagonists. It is believed that these agents act on afferent nerves in addition to smooth muscle. We investigated the effects of imidafenacin and 5-hydroxymethyl tolterodine on single unit afferent activity of mechanosensitive capsaicin sensitive and insensitive primary bladder afferent nerve fibers in rats. MATERIALS ANDMETHODS:
Female Sprague Dawley® rats were anesthetized. Single unit afferent activity was recorded from the L6 dorsal roots and classified by conduction velocity as that of Aδ or C fibers. After measuring control single afferent activity during constant filling cystometry the procedure was repeated with intravenous administration of imidafenacin (0.3 to 30 µg/kg) or 5-hydroxymethyl tolterodine (0.01 to 1 mg/kg) at cumulative doses with or without intravesical capsaicin or oxotremorine-M instillation.RESULTS:
A total of 139 single unit afferent fibers were isolated from 111 rats, including 19 Aδ and 120 C fibers. Neither imidafenacin nor 5-hydroxymethyl tolterodine significantly affected the overall single unit afferent activity of Aδ or C fibers. Based on capsaicin sensitivity C fibers were divided into capsaicin sensitive and insensitive groups. Each antimuscarinic inhibited the single unit afferent activity of capsaicin sensitive C fibers but not of capsaicin insensitive C fibers at the highest dose. Moreover, oxotremorine-M facilitated single unit afferent activity in a proportion of C fibers. The facilitated single unit afferent activity was significantly attenuated by the highest dose of imidafenacin.CONCLUSIONS:
These findings demonstrate that imidafenacin and 5-hydroxymethyl tolterodine can selectively inhibit capsaicin sensitive C fibers among mechanosensitive bladder afferents by antagonizing bladder muscarinic receptors.Palavras-chave
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Compostos Benzidrílicos
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Bexiga Urinária
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Capsaicina
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Antagonistas Muscarínicos
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Cresóis
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Fibras Nervosas Amielínicas
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Imidazóis
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Neurônios Aferentes
Tipo de estudo:
Diagnostic_studies
Limite:
Animals
Idioma:
En
Ano de publicação:
2015
Tipo de documento:
Article