Molecular neurobiology for practicing psychiatrists, part 2: how neurotransmitters activate second messenger systems

Chemical neurotransmission begins when receptor occupancy by a neurotransmitter is converted into an intracellular second messenger that carries the information from the neurotransmitter deep into the target neuron. For clinicians, it is this transfer of neurotransmitter information all the way to the genome that hypothetically explains the therapeutic actions of many psychotropic drugs. This also accounts for why drugs that modify neurotransmission may take time to fully develop their clinical actions.