Doxazosin-induced up-regulation of α1A-adrenoceptor mRNA in the rat lower urinary tract

• Published in: Canadian journal of physiology and pharmacology Vol. 82; no. 10; pp. 872 - 878
• Main Authors: Yono, Makoto, Foster, Jr, Harris E, Shin, David, Takahashi, Wataru, Pouresmail, Mehdi, Latifpour, Jamshid
• Format: Journal Article
• Language: English
• Published: Ottawa, Canada NRC Research Press 01.10.2004; National Research Council of Canada
• Subjects: Biological and medical sciences; Catecholaminergic system; Medical sciences; Neuropharmacology; Neurotransmitters. Neurotransmission. Receptors; Pharmacology. Drug treatments; Animal model; Doxazosin; Rat; Hyperplasia; Rodentia; α1-Adrenergic receptor; Urinary tract; Dose activity relation; Vertebrata; Mammalia; Alpha blocking agent; Treatment; Urinary system; α1A-adrenergic receptor; Animal; Antagonist; Urogenital system; Prostate
• ISSN: 0008-4212; 1205-7541
• DOI: 10.1139/y04-098

α 1 -adrenoceptor (AR) antagonists can provide effective treatment of symptoms caused by benign prostatic hyperplasia. However, their mechanisms of action have not been fully elucidated. We previously reported that chronic administration of doxazosin causes an up-regulation in the mRNA expression of all three α 1 -AR subtypes in the rat prostate. As α 1 -AR antagonists might also affect the properties of α 1 -ARs in the lower urinary tract, we examined the effects of doxazosin (2 or 4 mg/kg daily subcutaneously, supplemented with 4 mg/kg daily orally for 8 or 12 weeks) on α 1 -AR subtype mRNAs in the rat bladder dome, bladder base, and urethra using real-time reverse transcription PCR. Rats that received the highest doses of doxazosin had significantly heavier bladder base and prostatic urethra than controls. PCR data showed that all three α 1 -AR subtypes were expressed in all tissues studied. Doxazosin treatment caused an up-regulation in the mRNA levels of α 1A -AR in the rat bladder base and prostatic urethra, indicating that chronic doxazosin treatment may cause an alteration in the properties of α 1A -AR subtype mRNA in these two areas. Furthermore, the heavier bladder base and prostatic urethra in the doxazosin-treated rats suggest that α 1 -AR antagonist treatment might also influence the growth process in these areas of the rat lower urinary tract.Key words: α 1 -adrenoceptor, doxazosin, bladder, urethra.