Friday, June 27, 2008

Cigarettes and coffee for breakfast...why it's so easy to get stuck in that rut

My teaching assistant today comes from Star Wars. He is here with me, because I have lost track of the number of times, when trying to do a serious presentation about neurotransmitters, I have said, "R2D2" when I meant to say "DRD2". I will have to check the Universal Diagnostic and Statistical Manual to see if I meet the criteria for Intergalactical Dyslexia...

What R2D2 and I would like to tell you about his almost-namesake today, the DRD2 receptor, is that this subset of dopamine receptors is sensitive to how we eat. DRD2 is responsible for impulse control. People who have a disturbed DRD2 system are more prone to problems such as shoplifting, gambling, alcohol addiction, nicotine addiction, and binge eating. They also seem to have more intensive carbohydrate cravings.

Scientists recently reported that this receptor is especially sensitive to food restriction. That is, people who restrict their food intake seem to be more sensitive to the reinforcing effects (the effects that make you feel good and want to use) of several addictive substances, including opiates, nicotine, and psychostimulants.

(That is why R2D2 is a little wired today; he was running late and drank his coffee but skipped breakfast to be sure we got this posted.)

This particular study suggests that the same effect can be provoked when restricting food and using dopamine-promoting medications such as pramipexole (Mirapex). For anyone taking medications for Parkinson's disease or restless legs syndrome, this could be important information to discuss with a nutritionist.

One of the enhanced responses with food restriction is locomotion. And that makes me think of people who abuse some of these chemicals. They stimulate themselves, which suppresses their appetite, which enhances their stimulation and increases their physical activity. On an ongoing basis, (and people who abuse drugs tend to not only use them just once) that can create a calorie deficit which reinforces the positive effects of the drug use. And that can reinforce staying addicted.

Even if you're not using illicit drugs, maybe not eating and living on cigarettes and coffee is kind an offbeat, roundabout way to jumpstart the dopamine system into motion. I have had many, many clients who tell me they feel addicted to sugar, and when they simply don't eat it they feel better. Maybe this is one of the reasons for that relationship.

Just a little fun fact on this Friday that will hopefully give you something to think about.

R2D2 and I are now going to eat breakfast.

Collins GT, Calinski DM, Newman AH, Grundt P, Woods JH. Food restriction alters N'-propyl-4,5,6,7-tetrahydrobenzothiazole-2,6-diamine dihydrochloride (pramipexole)-induced yawning, hypothermia, and locomotor activity in rats: evidence for sensitization of dopamine D2 receptor-mediated effects. J Pharmacol Exp Ther. 2008 May;325(2):691-7.

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