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This Article Full Text Full Text (PDF) All Versions of this Article: 290/2/F486    most recent 00314.2005v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via ISI Web of Science (5) Citing Articles via Google Scholar Google Scholar Articles by Breen, L. T. Articles by Mutafova-Yambolieva, V. N. Search for Related Content PubMed PubMed Citation Articles by Breen, L. T. Articles by Mutafova-Yambolieva, V. N.

-NAD is a novel nucleotide released on stimulation of nerve terminals in human urinary bladder detrusor muscle

¹Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno; and ²Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada

Submitted 3 August 2005 ; accepted in final form 20 September 2005

Endogenous nucleotides with extracellular functions may be involved in the complex neural control of human urinary bladder (HUB). Using HPLC techniques with fluorescence detection, we observed that in addition to ATP and its metabolites ADP, AMP and adenosine, electrical field stimulation (EFS; 4–16 Hz, 0.1 ms, 15 V, 60 s) of HUB detrusor smooth muscle coreleases novel nucleotide factors, which produce etheno-1N⁶-ADP-ribose (eADPR) on etheno-derivatization at high temperature. A detailed HPLC fraction analysis determined that nicotinamide adenine dinucleotide (-NAD⁺; 7.0 ± 0.7 fmol/mg tissue) is the primary nucleotide that contributes to the formation of eADPR. The tissue superfusates collected during EFS also contained the -NAD⁺ metabolite ADPR (0.35 ± 0.2 fmol/mg tissue) but not cyclic ADPR (cADPR). HUB failed to degrade nicotinamide guanine dinucleotide (NGD⁺), a specific substrate of ADP ribosyl cyclase, suggesting that the activity of this enzyme in the HUB is negligible. The EFS-evoked release of -NAD⁺ was frequency dependent and is reduced in the presence of tetrodotoxin (TTX; 0.3 µmol/l), -conotoxin GVIA (50 nmol/l), and botulinum neurotoxin A (BoNT/A; 100 nmol/l), but remained unchanged in the presence of guanethidine (3 µmol/l), -agatoxin IVA (50 nmol/l), or charbachol (1 µmol/l). Capsaicin (10 µmol/l) increased both the resting and EFS-evoked overflow of -NAD⁺. Exogenous -NAD⁺ (1 µmol/l) reduced both the frequency and amplitude of spontaneous contractions. In conclusion, we detected nerve-evoked overflow of -NAD⁺ and ADPR in HUB. The -NAD⁺/ADPR system may constitute a novel inhibitory extracellular nucleotide mechanism of neural control of the human bladder.

synaptic transmission; purinergic; neurotransmitter; nucleotide; cotransmission