Nitric oxide (NO) is a gaseous messenger involved
in atypical forms of intercellular communications, able to exert
a strong functional modulation of several neurotransmitter
systems. In particular, NO heavily influences the excitatory
neurotransmitter glutamate, mainly through NMDA receptors,
and the inhibitory neurotransmitter GABA, mainly through
GABA A receptors. Due to the involvement of glutamate and
GABA in a delicate balance conditioning the functional status
of the neural cells, this interaction suggests a role for NO in
regulating neuronal excitability and its transition towards
hyperexcitability phenomena. This article reviews the main
knowledge about the relationships existing between the activity
of the NO system and the experimental aspects of epilepsy,
focusing on the somewhat antithetic findings about the
proconvulsant or the anticonvulsant roles exerted by nitric oxide
