Recreational Drugs and Synaptic Transmission

Recreational Drugs

Recreational drugs are substances taken for psychoactive effects without medical justification, affecting transmission in the CNS. They can be legal (alcohol, tobacco, caffeine) or illegal (cocaine, ecstasy, cannabis).

Key Concepts

• Psychoactive Drugs: Alter perception, mood, consciousness, cognition, and behavior.
• Limbic System: Regulates arousal, emotions, and mood.
• Dopamine Reward Pathway: Associated with feelings of reward.
• Euphoria: Intense pleasurable feeling.
• Dysphoria: Intense anxiety or dissatisfaction.
• Desensitisation: Requiring a higher dosage for the same effect due to loss of synaptic response.

Agonists and Antagonists

• Agonists: Stimulate receptors.
• Antagonists: Block receptor activation.

Specific Drugs and Their Effects

Nicotine

• Stimulant found in tobacco, acts as an agonist of acetylcholine receptors, leading to increased neurotransmission and dopamine release.

Cocaine

• Stimulant that blocks reuptake of monoamine neurotransmitters (dopamine, serotonin), prolonging their effects in the synapse.

Alcohol

• Initially boosts serotonin but long-term increases GABA activity, slowing down neurotransmission.

Cannabis (THC)

• Active ingredient is THC, a partial agonist of CB1 receptors affecting the cerebral cortex (cognitive effects), cerebellum (sedative effects), and brainstem (analgesic effects).

Stimulants

Increase neurotransmitter activity at the synapse.

• Nicotine: Mimics acetylcholine.
• Cocaine: Blocks dopamine re-uptake.

General Effects of Recreational Drugs

• Stimulants: Increase alertness.
• Sedatives: Slow down the CNS.
• Painkillers: Suppress pain receptors.
• Hallucinogens: Cause hallucinations.

Evaluation of Research

• Brain scanning techniques have improved, but accurately determining synaptic transmission levels remains difficult.
• Animal studies may not fully generalize to humans due to brain anatomy differences.