6.2.7
Medical Application
Excitatory Drugs
Excitatory Drugs
Many drugs affect nervous transmission at synapses. Excitatory drugs stimulate the nervous system producing more action potentials on the post-synaptic membrane. Excitatory drugs could:
Mimic neurotransmitters
Mimic neurotransmitters
- Drugs with a similar shape to neurotransmitters can mimic their function.
- The drug can bind to receptors on the postsynaptic membrane to produce an action potential.
- These drugs are called agonists.
- E.g. Nicotine can bind to nicotinic cholinergic receptors in the brain to mimic acetylcholine.
Inhibit enzymes
Inhibit enzymes
- Drugs can bind to enzymes to prevent the breakdown of a neurotransmitter.
- The neurotransmitter would continue to generate an action potential in the postsynaptic membrane.
- E.g. Nerve gas inhibits acetylcholinesterase and stops the breakdown of acetylcholine. This causes loss of muscle control.
Release of neurotransmitters
Release of neurotransmitters
- Drugs can cause presynaptic neurones to release neurotransmitters.
- More neurotransmitters will activate more receptors and an action potential is more likely to be created.
Inhibitory Drugs
Inhibitory Drugs
Many drugs affect nervous transmission at synapses. Inhibitory drugs inhibit the nervous system so that fewer action potentials are produced. Inhibitory drugs could:
Block calcium ion channels
Block calcium ion channels
- Drugs can block calcium ion channels in the presynaptic membrane.
- Blocking calcium ion channels would prevent the release of neurotransmitters from the presynaptic neurone.
- E.g. Alcohol.
Block receptors
Block receptors
- Drugs can block receptors on the postsynaptic membrane.
- If the receptors are blocked, neurotransmitters cannot bind and an action potential is not generated in the postsynaptic neurone.
- These drugs are called antagonists.
- E.g. Curare blocks nicotinic cholinergic receptors causing muscle paralysis.
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain
1.4.2Investigating Proteins
1.4.3Primary & Secondary Protein Structure
1.4.4Tertiary & Quaternary Protein Structure
1.4.5Enzymes
1.4.6Factors Affecting Enzyme Activity
1.4.7Enzyme-Controlled Reactions
1.4.8End of Topic Test - Lipids & Proteins
1.4.9A-A* (AO3/4) - Enzymes
1.4.10A-A* (AO3/4) - Proteins
1.5Nucleic Acids
1.6ATP
1.7Water
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
2.4Cell Recognition & the Immune System
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.1.1Overview of Photosynthesis
5.1.2Photoionisation of Chlorophyll
5.1.3Production of ATP & Reduced NADP
5.1.4Cyclic Photophosphorylation
5.1.5Light-Independent Reaction
5.1.6A-A* (AO3/4) - Photosynthesis Reactions
5.1.7Limiting Factors
5.1.8Photosynthesis Experiments
5.1.9End of Topic Test - Photosynthesis
5.1.10A-A* (AO3/4) - Photosynthesis
5.2Respiration
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis
6.4.2Blood Glucose Concentration
6.4.3Controlling Blood Glucose Concentration
6.4.4End of Topic Test - Blood Glucose
6.4.5Primary & Secondary Messengers
6.4.6Diabetes Mellitus
6.4.7Measuring Glucose Concentration
6.4.8Osmoregulation
6.4.9Controlling Blood Water Potential
6.4.10ADH
6.4.11End of Topic Test - Diabetes & Osmoregulation
6.4.12A-A* (AO3/4) - Homeostasis
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation
7.3.2Natural Selection & Evolution
7.3.3End of Topic Test - Populations & Evolution
7.3.4Types of Selection
7.3.5Types of Selection Summary
7.3.6Overview of Speciation
7.3.7Causes of Speciation
7.3.8Diversity
7.3.9End of Topic Test - Selection & Speciation
7.3.10A-A* (AO3/4) - Populations & Evolution
8The Control of Gene Expression (A2 only)
8.2Gene Expression
8.2.1Stem Cells
8.2.2Stem Cells in Disease
8.2.3End of Topic Test - Mutation & Gene Epression
8.2.4A-A* (AO3/4) - Mutation & Stem Cells
8.2.5Regulating Transcription
8.2.6Epigenetics
8.2.7Epigenetics & Disease
8.2.8Regulating Translation
8.2.9Experimental Data
8.2.10End of Topic Test - Transcription & Translation
8.2.11Tumours
8.2.12Correlations & Causes
8.2.13Prevention & Treatment
8.2.14End of Topic Test - Cancer
8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
Jump to other topics
1Biological Molecules
1.1Monomers & Polymers
1.2Carbohydrates
1.3Lipids
1.4Proteins
1.4.1The Peptide Chain
1.4.2Investigating Proteins
1.4.3Primary & Secondary Protein Structure
1.4.4Tertiary & Quaternary Protein Structure
1.4.5Enzymes
1.4.6Factors Affecting Enzyme Activity
1.4.7Enzyme-Controlled Reactions
1.4.8End of Topic Test - Lipids & Proteins
1.4.9A-A* (AO3/4) - Enzymes
1.4.10A-A* (AO3/4) - Proteins
1.5Nucleic Acids
1.6ATP
1.7Water
1.8Inorganic Ions
2Cells
2.1Cell Structure
2.2Mitosis & Cancer
2.3Transport Across Cell Membrane
2.4Cell Recognition & the Immune System
3Substance Exchange
3.1Surface Area to Volume Ratio
3.2Gas Exchange
3.3Digestion & Absorption
4Genetic Information & Variation
4.1DNA, Genes & Chromosomes
4.2DNA & Protein Synthesis
4.3Mutations & Meiosis
4.4Genetic Diversity & Adaptation
4.5Species & Taxonomy
4.6Biodiversity Within a Community
4.7Investigating Diversity
5Energy Transfers (A2 only)
5.1Photosynthesis
5.1.1Overview of Photosynthesis
5.1.2Photoionisation of Chlorophyll
5.1.3Production of ATP & Reduced NADP
5.1.4Cyclic Photophosphorylation
5.1.5Light-Independent Reaction
5.1.6A-A* (AO3/4) - Photosynthesis Reactions
5.1.7Limiting Factors
5.1.8Photosynthesis Experiments
5.1.9End of Topic Test - Photosynthesis
5.1.10A-A* (AO3/4) - Photosynthesis
5.2Respiration
5.3Energy & Ecosystems
6Responding to Change (A2 only)
6.1Nervous Communication
6.2Nervous Coordination
6.3Muscle Contraction
6.4Homeostasis
6.4.1Overview of Homeostasis
6.4.2Blood Glucose Concentration
6.4.3Controlling Blood Glucose Concentration
6.4.4End of Topic Test - Blood Glucose
6.4.5Primary & Secondary Messengers
6.4.6Diabetes Mellitus
6.4.7Measuring Glucose Concentration
6.4.8Osmoregulation
6.4.9Controlling Blood Water Potential
6.4.10ADH
6.4.11End of Topic Test - Diabetes & Osmoregulation
6.4.12A-A* (AO3/4) - Homeostasis
7Genetics & Ecosystems (A2 only)
7.1Genetics
7.2Populations
7.3Evolution
7.3.1Variation
7.3.2Natural Selection & Evolution
7.3.3End of Topic Test - Populations & Evolution
7.3.4Types of Selection
7.3.5Types of Selection Summary
7.3.6Overview of Speciation
7.3.7Causes of Speciation
7.3.8Diversity
7.3.9End of Topic Test - Selection & Speciation
7.3.10A-A* (AO3/4) - Populations & Evolution
8The Control of Gene Expression (A2 only)
8.2Gene Expression
8.2.1Stem Cells
8.2.2Stem Cells in Disease
8.2.3End of Topic Test - Mutation & Gene Epression
8.2.4A-A* (AO3/4) - Mutation & Stem Cells
8.2.5Regulating Transcription
8.2.6Epigenetics
8.2.7Epigenetics & Disease
8.2.8Regulating Translation
8.2.9Experimental Data
8.2.10End of Topic Test - Transcription & Translation
8.2.11Tumours
8.2.12Correlations & Causes
8.2.13Prevention & Treatment
8.2.14End of Topic Test - Cancer
8.2.15A-A* (AO3/4) - Gene Expression & Cancer
8.3Genome Projects
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