Biphasic Effect of Apomorphine, an Anti-Parkinsonian Drug, on Bladder Function in Rats. Neuroscience [Neuroscience] Journal article | | Title | Biphasic Effect of Apomorphine, an Anti-Parkinsonian Drug, on Bladder Function in Rats. | | Author(s) | Uchiyama T, Sakakibara R, Yoshiyama M, Yamamoto T, Ito T, Liu Z, Yamaguchi C, Awa Y, Yano H, Yanagisawa M, Yamanishi T, Hattori T, Kuwabara S | | Institution | Department of Neurology, Graduate School of Medicine, Chiba University, Chiba, Japan. | | Source | Neuroscience 2009 Jun 3. | | Abstract | The effects of anti-parkinsonian drugs on bladder function have been controversial; namely, some aggravated while others alleviated bladder dysfunction in patients with Parkinson disease. These studies, however, did not consider the dose- and time-dependent effects. Therefore, we investigated these effects of apomorphine, an anti-parkinsonian drug and a nonselective dopamine receptor agonist, on the bladder function using normal conscious rats. Consecutive cycles of micturition were analyzed for 30-min periods before and after (over a 4-h period) s.c. administration of a single dose of 0.01 (low), 0.05 (medium), 0.5 (high) mg/kg of apomorphine or saline to the rats. Apomorphine administration produced various effects in relevant urodynamic parameters, although the monitored parameters remained unchanged in saline-administered rats. During filling, low-dose apomorphine induced initial decreases in voiding frequency (VF; defined as the number of voiding during a 15-min period). However, medium- and high-dose apomorphine dose-dependently induced initial increases in VF, and followed by decreases in VF. These both doses also induced initial increase in threshold pressure. During voiding, low-dose apomorphine induced initial increases in micturition volume (MV), which reflected increase in bladder capacity (BC). However, medium- and high-dose apomorphine dose-dependently induced initial decreases in MV, and followed by increases in MV. These both doses also dose-dependently induced an initial increase in maximum bladder contraction pressure during the early phase after administration. The present study demonstrated that apomorphine displayed a dose- and time-dependent biphasic effect on the normal bladder filling function. These pharmacodynamic characteristics of apomorphine could be applicable to other anti-parkinsonian drugs such as levodopa and nonselective dopamine receptor agonists, and may account for the previous reported conflicting effects of anti-parkinsonian drugs on bladder dysfunction in patients with Parkinson disease, although it is needed to evaluate in disease status. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 19501134 |
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