Effects of nor-NOHA and heparin, in the absence and presence of l-NAME, and l-arginine on the responsiveness to intraluminally administered methacholine of intact perfused tracheae from ovalbumin-challenged guinea pigs
| Emax % KCl | pEC50 -log M | n | |
| Unchallenged | 51.6±1.2 | 3.12±0.20 | 6 |
| Ovalbumin challenged | 105.1±10.8** | 3.28±0.13 | 8 |
| + nor-NOHA 5.0 μM | 52.8±5.2## | 3.41±0.15 | 8 |
| + nor-NOHA 5.0 μM + l-NAME 1.0 mM | 104.8±11.1¶ | 3.48±0.16 | 4 |
| + heparin 250 U·mL−1 | 54.2±11.0# | 2.84±0.19 | 6 |
| + heparin 250 U·mL−1 + l-NAME 1.0 mM | 108.9±6.5+ | 3.25±0.08 | 4 |
| + l-arginine 5.0 mM | 67.6±11.0# | 3.16±0.15 | 8 |
Data are presented as mean±sem. nor-NOHA: Nω-hydroxy-nor-l-arginine; l-NAME: Nω-nitro-l-arginine methyl ester; Emax: maximal effect obtained in the presence of 10 mM methacholine; pEC50: -log half-maximal effective concentration (sensitivity towards methacholine). **p<0.01 compared with unchallenged control group; #: p<0.05; ##: p<0.01 compared with ovalbumin-challenged controls; and ¶: p<0.05 compared with nor-NOHA; +: p<0.05 compared with heparin.