Improvement of bladder storage function by α1-blocker depends on the suppression of C-fiber afferent activity in rats
| Autor: | Yoshitaka Aoki, Yoshiji Miwa, Osamu Yokoyama, Nobuyuki Oyama, Yosuke Matsuta, Hironobu Akino, Kazuya Tanase, Anwar Yusup |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Urology
Neurotoxins Urinary Bladder Resiniferatoxin Naphthalenes Piperazines Rats Sprague-Dawley chemistry.chemical_compound Desensitization (telecommunications) Afferent Muscle Hypertonia Occlusion medicine Animals Neurons Afferent Adrenergic alpha-Antagonists Injections Spinal Injections Intraventricular Nerve Fibers Unmyelinated Dose-Response Relationship Drug Naftopidil Cerebral infarction business.industry medicine.disease α1 blocker Rats Catheter chemistry Anesthesia Injections Intravenous Adrenergic alpha-1 Receptor Antagonists Female Neurology (clinical) Diterpenes business medicine.drug |
| Zdroj: | Neurourology and Urodynamics. 25:461-467 |
| ISSN: | 1520-6777 0733-2467 |
| Popis: | Aims α1-blockers improve voiding symptoms through the reduction of prostatic and urethral smooth muscle tone; however, the underlying mechanism of improvement of storage symptoms is not known. Using a rat model of detrusor overactivity caused by cerebral infarction (CI), we undertook the present study to determine whether the effect of an α1-blocker, naftopidil, is dependent on the suppression of C-fiber afferents. Methods To induce desensitization of C-fiber bladder afferents, we injected resiniferatoxin (0.3 mg/kg, RTX) sub-cutaneously to female Sprague-Dawley rats 2 days prior to left middle cerebral artery occlusion (MCAO) (RTX-CI rats). As controls we used rats without RTX treatment (CI rats). MCAO and insertion of a polyethylene catheter through the bladder dome were performed under halothane anesthesia. We investigated the effects on cystometrography (CMG) of intravenous (i.v.), intracerebroventricular (i.c.v.), or intrathecal (i.t.) administration of naftopidil in conscious CI rats. Results Bladder capacity (BC) was markedly reduced after MCAO in both RTX-CI and CI rats. I.v. administration of naftopidil significantly increased BC in CI rats without an increase in residual volume, but it had no effects on BC in RTX-CI rats. I.t. administration of naftopidil significantly increased BC in CI but not in RTX-CI rats. Conclusions These results suggest that naftopidil has an inhibitory effect on C-fiber afferents in the lumbosacral spinal cord, improving BC during the storage phase. Neurourol. Urodynam. © 2006 Wiley-Liss, Inc. |
| Databáze: | OpenAIRE |
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