Caption: Nicotine crystals. Nicotine is an organic compound, an alkaloid found naturally throughout the tobacco plant, with a high concentration in the leaves. It constitutes 0.3 to 5% of the plant by dry weight. The biosynthesis takes place in the roots and it is accumulated in the leaves. It is a potent nerve poison and is included in many insecticides. In lower concentrations, the substance is a stimulant and is one of the main factors leading to habit-forming qualities of tobacco smoking. In small doses nicotine has a stimulating effect, increasing activity, alertness and memory. As nicotine enters the body, it quickly gets distributed through the bloodstream and can cross the blood-brain barrier. On average it takes about seven seconds for the substance to reach the brain. It acts on the nicotinic acetylcholine receptors. In small concentrations it increases the activity of these receptors, among other things leading to an increased flow of adrenaline, a stimulating hormone. The release of adrenaline causes an increase in heart rate, blood pressure and respiration, as well as higher glucose levels in the blood. Nicotine alkaloids are also found in the leaves of the coca plant.
Magnification*: x40
Type: LM
Copyright 1985 Dennis Kunkel Microscopy, Inc.
Keywords: 900326-33,12.01.04,alkaloid,crystal,crystals,coca plant,increase heart rate,nerve poison,nicotinic acetylcholine receptors,nightshade family,organic compound,Solanaceae,stimulant,tobacco plant,tobacco leaf,tobacco smoke,nicotinic acetylcholine receptor,LM