Nicotine Pharmacodynamics

It is not only due to the pharmacokinetic properties of nicotine administered by smoking, mentioned earlier, that nicotine is as addicting as it is, its pharmacodynamics play an important role as well. Nicotine interacts with the nicotinic cholinergic receptors in both the central and peripheral nervous system. The effect of nicotine can be stimulating but in a high dose it can be dampening too, due to complex electrochemical processes.

Stimulation of the nicotinic cholinergic receptor causes the release of many different neurotransmitters including acetylcholine, norep-inephrine, dopamine, serotonin, beta-endorphin, gamma-aminobutyric acid, and glutamate. It also causes the release of hormones such as growth hormone, prolactin, vasopressin, and adrenocor-ticotropic hormone (ACTH).8

Smokers report many different pleasant, rewarding effects of their habit, such as arousal, relaxation (especially in stressful situations), improved attention, and an increased performance on certain tasks. Furthermore,nicotine can improve one's mood, reduce anxiety, relieve hunger, and prevent weight gain. Benowitz has linked these positive effects in a (hypothetical) model shown in Figure 28-2.8

Figure 28-1. The nicotine level in blood after smoking one cigarette an hour. Blood samples every 15 minutes. The vertical axis shows the nicotine level in the blood (ng/mL blood). On the horizontal axis, the time is indicated on a scale of 1-24. (From Goldstein.7 With permission from Oxford University Press.)

Figure 28-1. The nicotine level in blood after smoking one cigarette an hour. Blood samples every 15 minutes. The vertical axis shows the nicotine level in the blood (ng/mL blood). On the horizontal axis, the time is indicated on a scale of 1-24. (From Goldstein.7 With permission from Oxford University Press.)

DOPAMINE

—►

Pleasure, Appetite

Suppression

NOREPINEPHRINE

Arousal, Appetite

Suppression

ACETYLCHOLINE

Arousal, Cognitive

NICOTINE t'

Enhancement

VASOPRESSIN —

—►

Memory Improvement

\ * SEROTONIN

—►

Mood Modulation,

Appetite Suppression

* BETA-ENDORPHIN

Reduction of Anxiety

and Tension

Figure 28-2. Neurochemical effects of nicotine. (From Benowitz.8)

Figure 28-2. Neurochemical effects of nicotine. (From Benowitz.8)

A Disquistion On The Evils Of Using Tobacco

A Disquistion On The Evils Of Using Tobacco

Among the evils which a vitiated appetite has fastened upon mankind, those that arise from the use of Tobacco hold a prominent place, and call loudly for reform. We pity the poor Chinese, who stupifies body and mind with opium, and the wretched Hindoo, who is under a similar slavery to his favorite plant, the Betel but we present the humiliating spectacle of an enlightened and christian nation, wasting annually more than twenty-five millions of dollars, and destroying the health and the lives of thousands, by a practice not at all less degrading than that of the Chinese or Hindoo.

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