Answer:
A drug can be described as any chemical which effects the functioning of the body of an organism.
- Certain drugs like nicotine activate the cholinergic receptors. The cholinergic receptors are usually activated by Acetylcholine . When drugs such as nicotine activate the cholinergic receptors, it can influence the normal functioning of the brain.
- Certain drugs such as cocaine might increase the synaptic concentrations of certain neuron transmitters.
- Certain drugs cause the the release of monoamine neurotransmitters such as dopamine, norepinephrine from presynaptic neurons.
- Certain drugs might effect the biochemcial pathway for the transmission of neurons.