Effect of naftopidil on brain noradrenaline-induced decrease in arginine-vasopressin secretion in rats
Masaki Yamamoto1, Takahiro Shimizu2, Shogo Shimizu2
1Department of Pharmacology, Kochi Medical School, Kochi University, Nankoku 783-8505, Japan; Department of Pediatrics, Kochi Medical School, Kochi University, Nankoku 783-8505, Japan.
Journal of Pharmacological Sciences
|September 27, 2016
Summary
Naftopidil prevents a decrease in arginine-vasopressin (AVP) and reduces urine production caused by noradrenaline. This suggests naftopidil may counteract central nervous system effects impacting AVP secretion and urine output.
Area of Science:
- Pharmacology
- Urology
- Neuroscience
Background:
- Naftopidil, an alpha1-adrenoceptor antagonist, is known to reduce nocturnal polyuria in patients with lower urinary tract symptoms.
- The precise mechanism by which naftopidil influences nocturnal urine production remains incompletely understood.
Purpose of the Study:
- To investigate the effects of naftopidil on plasma arginine-vasopressin (AVP) levels and urine production in rats.
- To determine if naftopidil can counteract the effects of central noradrenaline (NA) administration on AVP and urine output.
Main Methods:
- Rats were pretreated with naftopidil before central administration of noradrenaline (NA).
- Plasma AVP levels were measured using ELISA.
- Urine volume and osmolality were assessed.
- Voiding behaviors were observed during light and dark cycles.
Main Results:
- Noradrenaline administration decreased plasma AVP levels and increased urine volume.
- Systemic pretreatment with naftopidil (30 mg/kg) suppressed these effects of NA.
- Naftopidil alone did not affect plasma AVP levels or urodynamic parameters.
Conclusions:
- Systemic naftopidil administration can prevent the decline in AVP secretion and increase in urine production induced by central noradrenergic stimulation in rats.
- These findings suggest a potential mechanism for naftopidil's efficacy in managing nocturnal polyuria.
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