Dr. Kerr: Your brain on cigarettes

<p>Cindy was smoking her first cigarette in over eight months. I knew how hard she had worked to quit, so I asked her why she started up again. Her answer surprised me: “I just didn't feel like myself. I didn't feel like me, and I wanted to feel like me again.” </p><p>I know many smart people who still smoke cigarettes. They are well aware of the risks. They've seen the black lungs and the oxygen tanks and the smoker's skin. They know that in addition to nicotine, there are more than 4,000 chemicals in every drag — toxins that include ammonia, arsenic, formaldehyde, butane, turpentine, and lead. </p><p>But they continue to smoke. They are hooked, and the addiction is powerful. Sometimes it helps to know the enemy, understanding what nicotine does when it enters the body.</p><p>Nicotine is a psychoactive drug that induces euphoria. Nicotine activates reward pathways — the circuitry within the brain that regulates feelings of pleasure. </p><p>When inhaled or ingested, nicotine heads straight to the brain. Within seconds it is bound to nicotinic-acetylcholine receptors, stimulating the release of many chemicals including serotonin, norepinephrine, and beta-endorphins. </p><p>Nicotine binding to the brain's nicotinic-acetylcholine receptors also increases the levels of dopamine, which increases the smoker's sense of well-being. Dopamine is believed to be the brain's way of providing reinforcement and reward for smoking — one of the keys to understanding this addiction. </p><p>The most recent smoking cessation medication currently on the market works on this dopamine pathway. It binds to the nicotinic-acetylcholine receptors, blocking nicotine's ability to increase dopamine. This medicine is only available by prescription and comes with a significant list of serious warnings; it's not a medication to be taken lightly.</p><p>Nicotine also activates the sympathetic nervous system, causing the adrenal glands to release epinephrine. Epinephrine is a stimulant, causing an increase in heart rate and blood pressure. It also increases blood glucose levels. The increased blood glucose levels combined with a loss of taste and smell make nicotine an excellent appetite suppressant. </p><p>Nicotine is a substance that can simultaneously cause relaxation and invigoration. Many smokers learn to control the effects of tobacco by changing the way they smoke. Short, quick puffs provide low nicotine levels which selectively enhance the actions of norepinephrine and dopamine. This causes an energizing and stimulating drug effect. </p><p>Longer, deeper drags provide a higher level of nicotine in the brain, selectively enhancing the effects of serotonin and natural opiates. This is soothing and helps ease body aches and pains. </p><p>There is a well-established connection between depression and smoking. Tobacco smoke acts as a mild anti-depressant in the brain. Smokers self-treating depression may be completely unaware of their depression because they have been treating it for years with cigarettes. Those with a history of depression have a more difficult time quitting, and are more likely to relapse. They may also experience greater symptoms of nicotine withdrawal when they quit, and could likely benefit from a doctor's supportive care.</p><p>All this information about nicotine makes it sound like a powerful and beneficial drug. It's a real shame that cigarettes are proven killers. Although nicotine goes directly to the brain, it also affects most other areas of the body. The physiologic side effects are many and include:</p><p><BL@199,12,11,10>Sleep disturbances</p><p><BL@199,12,11,10>Muscle tremors and pain</p><p><BL@199,12,11,10>Nausea, heartburn, and diarrhea</p><p><BL@199,12,11,10>Insulin resistance</p><p><BL@199,12,11,10>Increased tendency for blood to form clots</p><p><BL@199,12,11,10>Lung disease</p><p><BL@199,12,11,10>Increased risk of many cancers</p><p>Cindy is again trying to quit, and she struggles daily. She misses her lifestyle and her sense of self, but for the sake of her grandchildren she keeps struggling. If you or a loved one is giving up cigarettes, help them by understanding their struggle, and tell them how much you appreciate their efforts. Their brain and body are going through tremendous changes that affect almost every part of their sense of well-being. Quitting may be the most difficult and worthwhile challenge they have ever faced.</p><p>For more information go to: http://www.drugabuse.gov/tib/tobnico.html</p><p>Dr. Stacey Kerr, a longtime Sonoma County family physician, graduated from UC Davis Medical School and is certified in her specialty by the American Board of Family Medicine. Her columns are not intended as a substitute for hand-on medical advice or treatment. Consult your health care provider before adhering to any recommendations in this column. Email comments to drkerr@the-doctors-inn.com.</p>