Final answer:
Thiopental affects the brain by causing sedation, hypnosis, decreased cerebral blood flow, and respiratory depression. It terminates its action through redistribution in the body. High doses can lead to severe central nervous system depression.
Step-by-step explanation:
The effects of thiopental on the brain include sedation, hypnosis, decreased cerebral blood flow, and the potential for respiratory depression. As a central nervous system depressant, thiopental exerts these effects by enhancing the activity of the neurotransmitter GABA, leading to decreased brain activity. To terminate its action, thiopental redistributes from the brain to other tissues in the body, which reduces its concentration in the brain and diminishes its effects.
High doses of thiopental can induce sleep, cause motor disturbance, memory loss, and even lead to decreased respiratory function or death. Psychoactive drugs like thiopental generally function as either agonists or antagonists on neurotransmitters. As an agonist, thiopental increases GABA activity, which may explain the drug's ability to cause central nervous system depression, resulting in effects such as decreased blood flow to the brain and impaired motor and sensory function.