Effect of mesoionic 4-phenyl-5-(cinnamoyl)-1,3,4-thiadiazolium-2-phenylamine chloride derivative salts on the activities of the nitric oxide synthase and arginase of Leishmania amazonensis.

L-arginine is involved in the production of both nitric oxide (NO), mediated by nitric oxide synthase (NOS) and L-ornithine, by arginase activity. It is generally accepted that NO regulation occurs mainly at the transcriptional level of NOS. In a previous work we purported that there is evidence that Leishmania sp.

Nitric oxide synthase (NOS) characterization in Leishmania amazonensis axenic amastigotes.

Background: Although Leishmania virulence may be modulated by environmental and genetic factors of their mammalian hosts and sand fly vectors, molecular determinants of Leishmania sp. are the key elements. This work evidences that Leishmania amazonensis axenic amastigotes produce comparatively more NO than infective promastigotes.