C. Drugs regulating the functions of the central nervous system (Chapters 5-12)

In this Section:

5. General anesthetics

6. Ethyl alcohol

7. Hypnotics

8. Pain-relieving drugs (analgesics)

9. Antiepileptic drugs

10. Antiparkinsonian drugs

11. Psychotropic drugs

12. Analeptics

There are a substantial number of drugs that help to regulate CNS functions. They include various chemical compounds, affecting mental state and emotions, reducing perception of painful sensations, facilitating the development of sleep, causing general anesthesia, etc.

The basis of the CNS action of most neurotropic drugs is their ability to change the process of interneuronal (synaptic) transmission. Depending on the direction of effect, drugs of inhibiting and stimulating action are distinguished. Each of these groups can be further subdivided into drugs of general and selective action (Table 5.1).

The special features of drugs of general action are the lack of selective effects on certain centers or functions. They interfere with the CNS function on almost all its levels. General anesthetics are the typical example of such drugs. They have a marked inhibitory effect on the transmission in the central arches of reflexes in the brain, spinal cord and medulla oblongata. This suppresses the consciousness and inhibits sensitivity and most reflexes.

Drugs with so-called selective action mainly affect certain centers or functional systems without impairing the CNS function in general. Such drugs include analgesics (for example, opioids), antiparkinsonian drugs, anxiolytics, etc. The above mentioned groups of drugs differ according to their levels of selectivity of their effect on certain centers and functions of the CNS.

Table 5.1. Drugs affecting the central nervous system.

Neurotropic drugs can affect different stages of synaptic transmission (for excitatory and inhibitory synapses), in particular: