A.5: AHL - Neuropharmacology

Essential idea: Communication between neurons can be altered through the manipulation of the release and reception of chemical messengers.

Nature of science: 

Assessing risks associated with scientific research—patient advocates will often press for the speeding up of drug approval processes, encouraging more tolerance of risk. (4.5)

Understandings:

• Some neurotransmitters excite nerve impulses in postsynaptic neurons and others inhibit them.

• Nerve impulses are initiated or inhibited in post-synaptic neurons as a result of summation of all excitatory and inhibitory neurotransmitters received from presynaptic neurons.

• Many different slow-acting neurotransmitters modulate fast synaptic transmission in the brain.

• Memory and learning involve changes in neurons caused by slow-acting neurotransmitters.

• Psychoactive drugs affect the brain by either increasing or decreasing postsynaptic transmission.

• Anesthetics act by interfering with neural transmission between areas of sensory perception and the CNS.

• Stimulant drugs mimic the stimulation provided by the sympathetic nervous system.

• Addiction can be affected by genetic predisposition, social environment and dopamine secretion.

Applications and skills:

• Application: Effects on the nervous system of two stimulants and two sedatives.

• Application: The effect of anesthetics on awareness.

• Application: Endorphins can act as painkillers.

• Skill: Evaluation of data showing the impact of MDMA (ecstasy) on serotonin and dopamine metabolism in the brain.

Guidance:

• Examples of stimulants are nicotine, cocaine or amphetamines.

• Examples of sedatives are benzodiazepines, alcohol or tetrahydrocannabinol (THC).