Barbiturates  - drugs acts on CNS as  depressants , mild sedation to total  anesthesia .  source: http://luckynews.co.tv/ Neurotransmitters affecting  Depression/Anxiety Neurotransmitter  transmit signals from  neuron  across a  synapse . Contained in  synaptic vesicles  on presynaptic side Bind to receptors on the postsynaptic side Serotonin ,   GABA , Norepinephrine   and Epinephrine Released