Autocoids (Histamine and Serotonin)
COX pathway is inhibited by (PGI Nov 2012)
Aspirin inhibits COX irreversibly by acetylating one of its serine residues; return of COX activity depends on syn· thesis of fresh enzyme. Other NSAIDS like indomethacin, diclofenac etc are competitive and reversible inhibitors of COX, return of activity depends on their dissociation from the enzyme which is turn is governed by the pharmacokinetic characteristics of the compound.
Corticosteroids like betamethasone act by inhibiting phospholipase C.