Introduction to Central Nervous System Pharmacology
Jacqueline Rosenjack Burchum DNSc, FNP-BC, CNE
Central nervous system (CNS) drugs—agents that act on the brain and spinal cord—are used for medical and nonmedical purposes. Medical applications include relief of pain, suppression of seizures, production of anesthesia, and treatment of psychiatric disorders. CNS drugs are used nonmedically for their stimulant, depressant, euphoriant, and other “mind-altering” abilities.
Despite the widespread use of CNS drugs, knowledge of these agents is limited. Much of our ignorance stems from the anatomic and neurochemical complexity of the brain and spinal cord. (There are more than 50 billion neurons in the cerebral hemispheres alone.) We are a long way from fully understanding both the CNS and the drugs used to affect it.
Transmitters of the Central Nervous System
In contrast to the peripheral nervous system, in which only 3 compounds—acetylcholine, norepinephrine, and epinephrine—serve as neurotransmitters, the CNS contains at least 21 compounds that serve as neurotransmitters (Box 16.1). Furthermore, there are numerous sites within the CNS for which no transmitter has been identified, so it is clear that additional compounds, yet to be discovered, also mediate central neurotransmission.