The Effects of drugs on Synapses.

Neurotransmitters are chemicals that diffuse across the synaptic cleft at junctions between neurones, and muscles. They have specific shapes and therefore bind to specific receptors on the post-synaptic membrane. They are used to pass a nerve impulse from neurone to neurone. They are stored in tiny vesicles in the pre-synaptic knob when not in use.
Drugs however can interfere with these neurotransmitters. Some drugs inhibit the neurotransmitters, and others enhance their effect causing continuous action potentials.
Nicotine is a very common legal drug, and it is a similar shape to acetylcholine (a common neurotransmitter). It is an example of a drug that enhances nerve impulses. This means it can bind to acetylcholine receptors on post-synaptic membranes, opening sodium channels and causing an action potential. There are also at least five types of nicotine receptors throughout the nervous system. These have varying sensitivities to nicotine, ...