Abstract

Vincent proposes that the extracellular cGMP found in cerebellum after glutamate receptor activation is released mainly from Purkinje cells because in these neurons the presence of guanylate cyclase has been shown using monoclonal antibodies. It is uncertain, however, whether Purkinje cells are the only source of extracellular cGMP in the cerebellum. This commentary examines the possibility that glial and cerebellar granule cells may also participate in cGMP synthesis and release, Moreover, the hypothesis of transcellular metabolism of citrulline and arginine is discussed. [VINCENT]