Evidence that the nitrergic neurotransmitter and endothelium-derived relaxing factor might be S-nitrosothiols in the mouse corpus cavernosum


Buyukafsar K., Gocmen C. , Secilmis A., Karatas Y. , Gokturk S., Kalyoncu N.

ACTA MEDICA OKAYAMA, cilt.53, ss.209-215, 1999 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Cilt numarası: 53 Konu: 5
  • Basım Tarihi: 1999
  • Dergi Adı: ACTA MEDICA OKAYAMA
  • Sayfa Sayıları: ss.209-215

Özet

The effects of thimerosal, a sulfhydryl oxidizing agent on nitrergic, endothelium-dependent and -independent relaxations were investigated to examine the possibility that the nitrergic neurotransmitter and endothelium-derived relaxing factor (EDRF) could be S-nitrosothiol or free nitric oxide (NO) in the isolated mouse corpus cavernosum, Thimerosal (5 X 10(-6) - 2 X 10(-5) M) inhibited or almost abolished electrical field stimulation-(EFS, 30V, 0.5 ms, 15 sec, 1, 2, 4, 8, 16 Hz), acetylcholine-(ACh, 5 X 10(-8) - 1.25 X 10(-6) M), glyceryl trinitrate-(GTN, 3 X 10(-7) - 3 X 10(-6) M), and S-nitrosoglutathione-(GSNO, 5 X 10(-6) - 1.25 X 10(-4) M) induced relaxations, Thiomerosal inhibition seems to be specific to L-arginine NO pathways since it had no effect on acidified sodium nitrite-(10(-4) - 5 X 10(-4) M), photoactivated sodium nitrite-(2 X 10(-4) M), isoprenaline-(10(-6) M), or papaverine-(10(-4) M) elicited relaxations. Moreover, the inhibitory effect of thimerosal on the nitrergic, ACh- or GTN-induced relaxations were partly reversed by sulfhydryl-containing compounds, L-cysteine (10(-3) M), dithiothreitol (10(-3) M), or glutathione (10(-3) M). However L-methionine (10(-3) M), which contains a methyl group on the sulphur atom, failed to restore the thimerosal inhibition. Thimerosal did not change the contraction produced by 10(-4) M N-G-nitro-L-arginine methyl ester, These findings indicate that the nitrergic neurotransmitter as well as EDRF may not be free NO but NO-transferring molecules, probably S-nitrosothiols,in the mouse corpus cavernosum.