iNOS induction does not cause hyperreactivity to 5-HT.
“In vitro” the hyperreactivity to 5-HT is explained by the inhibition of NOSs with L-NAME. If we put enough L-Arg to displace L-NAME we revert the hyperreactivity to 5-HT, but not the reduced BK responses. There are several possible explanations, one of them is that eNOS is
not functional and the source of NO is iNOS.