1 The possible existence of a b 3 -adrenergic receptor (b 3 -AR) in the human detrusor muscle was investigated by in vitro functional studies and analysis of mRNA expression. 2 Isoprenaline, noradrenaline and adrenaline each produced a concentration-dependent relaxation of the human detrusor. The rank order for their relaxing potencies was isoprenaline (pD 2 6.37+0.07) 5 noradrenaline (pD 2 6.07+0.12) 5 adrenaline (pD 2 5.88+0.11). 3 Neither dobutamine (b 1 -and b 2 -AR agonist) nor procaterol (b 2 -AR agonist) produced any signi®cant relaxation at concentrations up to 10 75 M. BRL37344A, CL316243 and CGP-12177A (b 3 -AR agonists), relaxed the preparations signi®cantly at concentrations higher than 10 76 M. The pD 2 values for BRL37344A, CL316243 and CGP-12177A were 6.42+0.25, 5.53+0.09 and 5.74+0.14, respectively. 4 CGP-20712A (10 77 ± 10 75 M), a b 1 -AR antagonist, did not a ect the isoprenaline-induced relaxation. On the other hand, ICI-118,551, a b 2 -AR antagonist, produced a rightward parallel shift of the concentration-relaxation curve for isoprenaline only at the highest concentration used (10 75 M) and its pK B value was 5.71+0.19. Moreover, SR58894A (10 77 ± 10 75 M), a b 3 -AR antagonist, caused a rightward shift of the concentration-relaxation curve for isoprenaline in a concentration-dependent manner. The pA 2 value and slope obtained from Schild plots were 6.24+0.20 and 0.68+0.31. 5 The b 1 -, b 2 -and b 3 -AR mRNAs were all positively expressed in detrusor smooth muscle preparations in a reverse transcription polymerase chain reaction assay. 6 In conclusion, the present results provide the ®rst evidence for the existence of the b 3 -AR subtype in the human detrusor. They also suggest that the relaxation induced by adrenergic stimulation of the human detrusor is mediated mainly through b 3 -AR activation.

beta-adrenoceptor stimulation is an effective way of relaxing the human detrusor and the effect is similar in normal and neurogenic bladders. A major portion of the relaxant effect of isoproterenol is mediated via beta3-adrenoceptor stimulation. Clinical trials may reveal whether this method is useful for treating bladder overactivity.

We reviewed 55 patients with urinary tract dysfunction owing to the tethered spinal cord syndrome, a form of spina bifida occulta with or without mild myelodysplasia, to evaluate the effects of neurosurgical treatment. Of the patients 24 underwent laminectomy with release of a tethered spinal cord and 31 were followed without the operation. Median followup was approximately 5 years. Urological findings at the most recent examination were compared between the 2 groups. In the operated group 5 patients, including 2 with myelodysplasia, apparently were cured of urinary tract dysfunction and 6, including 2 with myelodysplasia, had somewhat satisfactory results, whereas in the unoperated group only 4 patients had satisfactory results and the remainder were unaffected. Urinary tract dysfunction in some patients with spina bifida occulta may be relieved by surgical release of a tethered spinal cord.