TY - JOUR
T1 - Nitric oxide modulates neuropeptide Y regulation of ion transport in mouse ileum
AU - Rao, R. K.
AU - Lopez, Y.
AU - Riviere, P. J.M.
AU - Pascaud, X.
AU - Junien, J. L.
AU - Porreca, F.
N1 - Funding Information:
P4/7 Altered NPY-immunoreactivity in the Rat Superior Cervical Ganglion After Preganglionlc Transection of the Cervical Sympathetic Trunk N. Borghini and C. Heym Institut of Anatomy and Cell Biology, University of Heidelberg, Im Neuenheimer Feld 307, D-69 120 Heidelberg, Germany The importance of preganglionic afferences in the occurrence of two antigens known to be co-localized in a major population of rat superior cervical ganglion (SCG) neurons were light and electromnicroscopically investigated, in vivo. 1) the rate-limiting enzyme of catecholamine synthesis, tyrosine hydroxylase (TH) and 2) neuropeptide Y (NPY), that plays an important role in sympathetic neurophysiology. in this report, we focused our efforts on the distribution and subcellular localization of NPY-immunoreactivity in the rat SCG before and 6 days after decentralization of the ganglion. 3 modifications were visualized in the decentralized rat SCG: 1) amarkedreduc-tion in the intensity of immunofluorescence in cell bodies of postganglionic neurons (PGN), both with TH and NPY antisera; 2) the appearance of NPY-ir varicose fibres, as a rule non-immunoreactive for TH and identified as axonal processes by the somatodendritic microtubule-associated protein 2; 3) the formation of NPY-positive asymmetrical synapses onto dendritic processes of PGN. The findings demonstrate that NPY-ir PGN are activated by preganglionic perturbation. The increase in num- ber of NPY-ir nerve fibres suggests increased synthesis and transport of neuronal NPY. The results also indicate that NPY may play a key role in neuronal plasticity and remodeling capacity of the rat SCG. It is likely that newly formed synaptic connections restore the loss of synaptic input induced by preganglionic deafferentation. The data suggest that in addition to its neuromodulatory role, NPY in the rat SCG may function as a real transmitter. This research was supported by a grant from the German Research Foundation (Zi/22-1).
PY - 1996/7
Y1 - 1996/7
N2 - The possible involvement of nitric oxide in the regulation of intestinal ion transport induced by neuropeptide Y (NPY) was investigated by evaluating the effects of N(G)-methyl-L-arginine (L-NMA), L-arginine and S-nitroso-N - acetylpenicillamine (SNAP) on NPY activity in mouse ileum mounted in Ussing chambers in vitro. Serosal NPY (10 nM) produced a sustained decrease in basal transmural short circuit current (I(sc)) and potential difference without altering the tissue conductance. Pretreatment of tissues with L-arginine (3 mM), but not o-arginine (10 mM), blocked the NPY-mediated changes in I(sc). This L-arginine effect on NPY activity was reversed by L-NMA (3 mM), and not by N(G)-methyl-D-arginine (10 mM). The L-arginine effect on NPY activity was concentration-related with an A50 (95% CL) value of 1.6 (0.9-2.3) mM. In contrast to L-arginine, L-NMA (1 mM) pretreatment of tissues produced an enhancement of NPY activity, resulting in a 3.8-fold leftward displacement of the NPY concentration-response curve; N(G)-methyl-D-arginine was with out effect. The effect of L-NMA on NPY activity was concentration-related with an A50 (95% CL) value of 45.3 (23.2-68.8) μM. Serosal application of SNAP, a nitric oxide donor, produced a concentration-related decrease in basal I(sc) and potential difference without altering tissue conductance with an A50 (95% CL) value of 22.5 (11.1-40.5) μM. Pretreatment of tissue with SNAP (100 μM) reduced the NPY activity with rightward displacement of NPY concentration-response curve. Pretreatment of tissues with L-arginine also blocked the reduction of I(sc) by [D-Pen2,D-Pen5]enkephalin (10-30 nM), H2N-Tyr-D-Ala-Phe-Glu-Val-Val-Gly-NH2 (10-30 nM) and somatostatin (0.3-1.0 μM), but had no effect on norepinephrine (0.1-0.3 μM)-induced decrease in mouse ileal I(sc). These results show that [fgc]I-arginine and SNAP block NPY-mediated changes in ion transport, suggesting that nitric oxide may play a role in the regulation of NPY-mediated ion transport in the mouse ileum.
AB - The possible involvement of nitric oxide in the regulation of intestinal ion transport induced by neuropeptide Y (NPY) was investigated by evaluating the effects of N(G)-methyl-L-arginine (L-NMA), L-arginine and S-nitroso-N - acetylpenicillamine (SNAP) on NPY activity in mouse ileum mounted in Ussing chambers in vitro. Serosal NPY (10 nM) produced a sustained decrease in basal transmural short circuit current (I(sc)) and potential difference without altering the tissue conductance. Pretreatment of tissues with L-arginine (3 mM), but not o-arginine (10 mM), blocked the NPY-mediated changes in I(sc). This L-arginine effect on NPY activity was reversed by L-NMA (3 mM), and not by N(G)-methyl-D-arginine (10 mM). The L-arginine effect on NPY activity was concentration-related with an A50 (95% CL) value of 1.6 (0.9-2.3) mM. In contrast to L-arginine, L-NMA (1 mM) pretreatment of tissues produced an enhancement of NPY activity, resulting in a 3.8-fold leftward displacement of the NPY concentration-response curve; N(G)-methyl-D-arginine was with out effect. The effect of L-NMA on NPY activity was concentration-related with an A50 (95% CL) value of 45.3 (23.2-68.8) μM. Serosal application of SNAP, a nitric oxide donor, produced a concentration-related decrease in basal I(sc) and potential difference without altering tissue conductance with an A50 (95% CL) value of 22.5 (11.1-40.5) μM. Pretreatment of tissue with SNAP (100 μM) reduced the NPY activity with rightward displacement of NPY concentration-response curve. Pretreatment of tissues with L-arginine also blocked the reduction of I(sc) by [D-Pen2,D-Pen5]enkephalin (10-30 nM), H2N-Tyr-D-Ala-Phe-Glu-Val-Val-Gly-NH2 (10-30 nM) and somatostatin (0.3-1.0 μM), but had no effect on norepinephrine (0.1-0.3 μM)-induced decrease in mouse ileal I(sc). These results show that [fgc]I-arginine and SNAP block NPY-mediated changes in ion transport, suggesting that nitric oxide may play a role in the regulation of NPY-mediated ion transport in the mouse ileum.
UR - http://www.scopus.com/inward/record.url?scp=0030434271&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030434271&partnerID=8YFLogxK
M3 - Article
C2 - 8764351
AN - SCOPUS:0030434271
SN - 0022-3565
VL - 278
SP - 193
EP - 198
JO - Journal of Pharmacology and Experimental Therapeutics
JF - Journal of Pharmacology and Experimental Therapeutics
IS - 1
ER -