α₁‐, α₂‐ and β‐adrenoceptors in the urinary bladder, urethra and prostate

Abstract

1 We have systematically reviewed the presence, functional responses and regulation of a 1 -, a 2 -and b-adrenoceptors in the bladder, urethra and prostate, with special emphasis on human tissues and receptor subtypes. 2 a 1 -Adrenoceptors are only poorly expressed and play a limited functional role in the detrusor. a 1 -Adrenoceptors, particularly their a 1A -subtype, show a more pronounced expression and promote contraction of the bladder neck, urethra and prostate to enhance bladder outlet resistance, particularly in elderly men with enlarged prostates. a 1 -Adrenoceptor agonists are important in the treatment of symptoms of benign prostatic hyperplasia, but their beneficial effects may involve receptors within and outside the prostate. 3 a 2 -Adrenoceptors, mainly their a 2A -subtype, are expressed in bladder, urethra and prostate. They mediate pre-junctional inhibition of neurotransmitter release and also a weak contractile effect in the urethra of some species, but not humans. Their overall post-junctional function in the lower urinary tract remains largely unclear. 4 b-Adrenoceptors mediate relaxation of smooth muscle in the bladder, urethra and prostate. The available tools have limited the unequivocal identification of receptor subtypes at the protein and functional levels, but it appears that the b 3 -and b 2 -subtypes are important in the human bladder and urethra, respectively. b 3 -Adrenoceptor agonists are promising drug candidates for the treatment of the overactive bladder. 5 We propose that the overall function of adrenoceptors in the lower urinary tract is to promote urinary continence. Further elucidation of the functional roles of their subtypes will help a better understanding of voiding dysfunction and its treatment.

Is the Neutrophil-Lymphocyte Ratio an Indicator of Progression in Patients with Benign Prostatic Hyperplasia?

“…The main medications used to manage BPH are α 1-adrenoreceptor antagonists, which function by inhibiting the effects of endogenously released noradrenaline on prostate smooth muscle cells, thereby reducing prostate tone and obstruction of the bladder outlet (Michel and Vrydag, 2006). The neutrophil-lymphocyte ratio (NLR) can be calculated easily from complete blood counts and is an easily accessible marker which indicates the state of inflammation in the body.…”

The Effect of Combined Therapy with Tamsulosin Hydrochloride and Meloxicam in Patients with Benign Prostatic Hyperplasia Symptoms and Impact on Nocturia and Sleep Quality

“…Contraction of the human prostate is mediated predominantly, if not exclusively, by alpha-1A-adrenoceptors (3). Alpha blocker agents have been used for more than a decade in the treatment of LUTS.…”

Tools to study β3-adrenoceptors

“…Meanwhile, a role for β 3 -adrenoceptors has been established in blood vessels (Guimaraes and Moura 2001;Rozec and Gauthier 2006) and the urinary bladder (Michel and Vrydag 2006). Based upon such information, a systematic search for β 3 -adrenoceptor agonists and antagonists has been initiated, and some of these agonists have entered clinical drug development.…”