Central Neurotransmitters and Criteria

Introduction

• Neurotransmission — the process by which one neuron communicates with another neuron or effector cell across a specialised contact — the synapse; the central concept of neuropsychopharmacology is that drugs improving neurological/psychiatric disease act chiefly by enhancing or blunting CNS neurotransmission.
• Central neurotransmitters — endogenous chemicals that carry, boost and modulate signals across a chemical synapse, acting on specific targets; the precise number is unknown but >100 chemical messengers are identified, and a single neuron may release several transmitters.
• Therapeutic breadth — CNS-transmitter pharmacology underlies treatment of anxiety, depression, mania, schizophrenia, pain, fever, movement disorders, insomnia, eating disorders, nausea/vomiting and migraine — and the abuse liability of several CNS drugs.
• Two goals of CNS pharmacology — (i) using drugs as biochemical probes to manipulate the normal CNS, and (ii) developing drugs to correct pathophysiology in the abnormal CNS.
• The synapse — site of interneuronal communication, marked by accumulations of tiny (50–150 nm) synaptic vesicles and specialised active-zone proteins governing storage, docking, secretion and reaccumulation; the blood–brain barrier restricts charged solutes but a large-amino-acid transporter allows l-DOPA to enter (basis of its use in Parkinson disease).