Nicotine (Figure 6) is a naturally occurring alkaloid found within the baccy plant. It acts as a stimulant evoking pleasure in those who root on it, forming the basis of addiction. The drug has carcinogenic effects, causing inhibition of the resistive system to destroy cancerous cells. However it does not score along the synthesis of cancer within healthy cells.
It is also a potent nerve poison, being used in umpteen agricultural insecticides.
Figure 6: Chemical skeleton of nicotine
pharmacological medicine and Physiology of Nicotine
Nicotine acts by binding to nicotinic acetylcholine receptors (nAChRs) which atomic number 18 ligand-gated ion channels. The nAChRs ar made up of five polypeptide subunits forming a central water-filled channel (Cooper et al, 1991), which in the ease up state is permeable to cations. There are different subtypes of nAChRs achievable depending on what subunits they consist of. The greatest distinctions between subtypes are whether they are homo-oligomeric or made up of an ??-combination of subunits. Combinations of subunits exist from ?2-?6 and ?2-?4 and the only mammalian homo-oligomeric receptor subtype abundant in the central offensive system is the ?7 (Dani et al., 2001).
It is important to be aware that different subtypes exist, because, although any(prenominal) subtypes share similar pharmacological and physiological properties others differ in that aspect e.g. the kinetics and calcium permeability of ?7 homo-oligomeric receptors are faster and higher respectively than other subtypes while the ?4?2 receptors vex higher nicotine affinity (Dani et al., 2001).
Nicotinic Acetylcholine Receptors are invest on all ganglionic neurones and when nicotine is taken into the body via smoking, it acts on these receptors to have a major effect on the harmonised nervous system. (Sixth Edition Human Anatomy and Physiology, Elaine N.Marieb 2004). In low concentrations nicotine stimulates sympathetic ganglionic transmission but in high concentrations it paralyzes them completely...If you want to get a full essay, order it on our website: Ordercustompaper.com
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