Endogenous hydrogen sulfide has a powerful role in inhibitory neurotransmission to the pig bladder neck.
OBJECTIVE
We investigated the possible involvement of H2S in nitric oxide independent inhibitory neurotransmission to the pig bladder neck.


METHODS
We used immunohistochemistry to determine the expression of the H2S synthesis enzymes cystathionine γ-lyase and cystathionine β-synthase. We also used electrical field stimulation and myographs for isometric force recordings to study relaxation in response to endogenously released or exogenously applied H2S in urothelium denuded, phenylephrine precontracted bladder neck strips under noradrenergic, noncholinergic, nonnitrergic conditions.


RESULTS
Cystathionine γ-lyase and cystathionine β-synthase expression was observed in nerve fibers in the smooth muscle layer. Cystathionine γ-lyase and cystathionine β-synthase immunoreactive fibers were also identified around the small arteries supplying the bladder neck. Electrical field stimulation (2 to 16 Hz) evoked frequency dependent relaxation, which was decreased by DL-propargylglycine and abolished by tetrodotoxin (blockers of cystathionine γ-lyase and neuronal voltage gated Na(+) channels, respectively). The cystathionine β-synthase inhibitor O-(carboxymethyl)hydroxylamine did not change nerve mediated responses. The H2S donor GYY4137 (0.1 nM to 10 μM) induced potent, concentration dependent relaxation, which was not modified by neuronal voltage gated Na(+) channels, or cystathionine γ-lyase or cystathionine β-synthase blockade.


CONCLUSIONS
Results suggest that endogenous H2S synthesized by cystathionine γ-lyase and released from intramural nerves acts as a powerful signaling molecule in nitric oxide independent inhibitory transmission to the pig bladder neck.
Departamento de Fisiología, Facultad de Farmacia, Universidad Complutense de Madrid, Madrid, Spain.
Vítor S
VS
Fernandes
Ana S F
AS
Ribeiro
María Pilar
MP
Martínez
Luis M
LM
Orensanz
María Victoria
MV
Barahona
Ana
A
Martínez-Sáenz
Paz
P
Recio
Sara
S
Benedito
Salvador
S
Bustamante
Joaquín
J
Carballido
Albino
A
García-Sacristán
Dolores
D
Prieto
Medardo
M
Hernández
D000818:Animals; D005260:Female; D006862:Hydrogen Sulfide / Q000378:metabolism; D008297:Male; D013552:Swine; D009435:Synaptic Transmission / Q000502:physiology*; D001743:Urinary Bladder / Q000502:physiology*
D006862:Hydrogen Sulfide