dextromethorphan and cloperastine

Clinically, both overactive bladder (OAB) and dysuria are known to occur in patients with cerebral infarction (CI). A few anticholinergic drugs are used to treat OAB in such patients, although the effect is not satisfactory. On the other hand, little or no therapeutic drug is available for dysuria after CI. We previously reported that dextromethorphan (DM) and cloperastine (CP), centrally acting antitussives, reduce the frequency of micturition reflex and increase the threshold pressure in anesthetized rats. In this article, we describe the effects of DM and CP on urinary disturbances at 24 h after CI, induced by occlusion of the left middle cerebral artery in conscious rats. We also briefly review the structure, function, and distribution of G-protein-coupled inwardly rectifying K(+) (GIRK) channels in the brain, since both drugs have potent inhibitory effect on GIRK channel-activated currents in brain neurons. Of the two drugs, CP at antitussive-effective doses ameliorated both OAB and dysuria 24 h after CI in rats. On the other hand, DM aggravated the dysuria, although it significantly ameliorated the OAB. These results suggest that CP may have some therapeutic value for the treatment of OAB and dysuria after CI. At the present time, mechanisms of the effect of CP are unknown. However, several lines of evidence including pharmacological findings support the idea that the effects of CP may be produced at least partly by an increase in the level of 5-HT in the brain through an inhibitory effect on GIRK channel-activating currents.

Topics: Animals; Antitussive Agents; Brain; Cerebral Infarction; Dextromethorphan; Drug Design; Dysuria; G Protein-Coupled Inwardly-Rectifying Potassium Channels; Humans; Molecular Targeted Therapy; Piperidines; Rats; Serotonin; Urinary Bladder, Overactive

We investigated the effects of the centrally acting antitussives dextromethorphan and cloperastine on urinary bladder dysfunction 24 h after cerebral infarction in rats using the cystometry technique. First, cystometrography was performed in conscious male Sprague-Dawley rats. Cerebral infarction was then induced by occlusion of the left middle cerebral artery. Twenty-four hours after cerebral infarction, the effect of each drug on micturition disorder was estimated for 5 parameters: bladder capacity, maximum voiding pressure, micturition latency, flow rate, and urethral resistance. Cerebral infarction markedly reduced bladder capacity, micturition latency, and flow rate and increased urethral resistance. After cerebral infarction, intravenous dosing of saline had no effect on these parameters. Dextromethorphan (20 mg/kg) and cloperastine (2.5 and 5.0 mg/kg) at antitussive effective doses significantly increased bladder capacity and micturition latency. Unlike dextromethorphan, cloperastine ameliorated decreases in flow rate and increases in urethral resistance caused by cerebral infarction. These results suggest that cloperastine may have therapeutic value for the treatment of disorders of the micturition reflex associated with cerebral infarction, and that the drug may become a base compound from which to develop more active drugs for such disorders.

Topics: Animals; Antitussive Agents; Ataxia; Dextromethorphan; Diagnostic Techniques, Urological; Infarction, Middle Cerebral Artery; Male; Piperidines; Rats; Rats, Sprague-Dawley; Urinary Bladder; Urinary Bladder, Overactive; Urination