Intravenous anaesthetics have diverse effects on neurones within the c
entral nervous system. Only those that occur at clinical concentration
s are likely to be relevant. The dominant effect of many agents is the
potentiation of the inhibitory neurotransmitter gamma amino butyric a
cid (GABA) by various mechanisms while inhibiting the effects of excit
atory transmitters seems to be less dominant, except for ketamine.