Nicotine can act upon the central and peripheral nervous system. And its rapt effects include increase blood pressure and heart rate, constriction of arteries, and stimulation of the CNS. Once the nicotine is in the brain it activates receptors called cholinergic receptors.
Nicotine on direct application in humans causes irritation and burning sensation in the mouth and throat, increased salivation, nausea, abdominal pain, vomiting and diarrhea.
