Sympathetic contribution to bladder outlet obstructions: Quantitative analysis of tissue catecholamine content

Purinergic signalling in the urinary tract in health and disease

Purinergic signalling is involved in a number of physiological and pathophysiological activities in the lower urinary tract. In the bladder of laboratory animals there is parasympathetic excitatory cotransmission with the purinergic and cholinergic components being approximately equal, acting via P2X1 and muscarinic receptors, respectively. Purinergic mechanosensory transduction occurs where ATP, released from urothelial cells during distension of bladder and ureter, acts on P2X3 and P2X2/3 receptors on suburothelial sensory nerves to initiate the voiding reflex, via low threshold fibres, and nociception, via high threshold fibres. In human bladder the purinergic component of parasympathetic cotransmission is less than 3 %, but in pathological conditions, such as interstitial cystitis, obstructed and neuropathic bladder, the purinergic component is increased to 40 %. Other pathological conditions of the bladder have been shown to involve purinoceptor-mediated activities, including multiple sclerosis, ischaemia, diabetes, cancer and bacterial infections. In the ureter, P2X7 receptors have been implicated in inflammation and fibrosis. Purinergic therapeutic strategies are being explored that hopefully will be developed and bring benefit and relief to many patients with urinary tract disorders.

Effects of prazosin in men with symptoms of bladder neck obstruction and a non-hyperplastic prostate

In a double blind cross-over study, the selective alpha 1-adrenoceptor blocker prazosin was given to eleven men with a non-hyperplastic prostate and with symptoms of bladder neck obstruction. During prazosin treatment maximum and average flow rates increased and residual urine was reduced. Prazosin did not change any pressure variables recorded. All patients had antegrade ejaculation and no side effects were reported. It is concluded that in selected patients with bladder outlet obstruction, prazosin may be a therapeutic alternative to bladder neck incision.