Overview: For smokers, the first cigarette of the day is often accompanied by a cup of coffee. Researchers say this may be more than a habit, finding chemical compounds in roasted coffee beans may help suppress the effects of morning nicotine cravings.
Source: University of Florida
For some smokers, the first cigarette of the day is not as satisfying without a cup of coffee. That may be more than just a morning habit: Chemical compounds in roasted coffee beans may alleviate the effects of morning nicotine cravings, University of Florida researchers found.
In a cell-based study, the researchers identified two compounds in coffee that directly affect certain highly sensitive nicotinic receptors in the brain. In smokers, these brain receptors can be hypersensitive after a night of nicotine withdrawal.
The recently published findings have yet to be tested in humans, but are an important step toward understanding how coffee and cigarettes affect nicotine receptors in the brain, said Roger L. Papke, Ph.D., a professor of pharmacology at UF College. of Medicine. Caffeine is the feel-good ingredient in coffee for most people, but smokers can get a different kind of boost.
“Many people like caffeine in the morning, but there are other molecules in coffee that may explain why cigarette smokers want their coffee,” Papke said.
The researchers applied a dark-roasted coffee solution to cells that express a particular human nicotine receptor. An organic chemical compound in coffee may help restore nicotine receptor dysfunction that leads to nicotine cravings in smokers, the researchers concluded.
The findings led Papke to a broader hypothesis: One of the compounds in brewed coffee, known as n-MP, may help suppress cravings for nicotine in the morning.
Papke said he was intrigued by the idea that nicotine-dependent smokers associate tobacco use with coffee in the morning and alcohol in the evening. While the effect of alcohol on nicotinic receptors in the brain has been thoroughly investigated, the interaction of the receptors with coffee has been less studied.
“Many people look for coffee in the morning because of the caffeine. But did the coffee do anything different to smokers? We wanted to know if there were other things in coffee that affect the nicotine receptors in the brain,” Papke said.
The findings, he said, provide a good foundation for behavioral scientists who could further study nicotine withdrawal in animal models.
About this neuroscience research news
Author: Doug Bennett
Source: University of Florida
Contact: Doug Bennett – University of Florida
Image: The image is in the public domain
Original research: Closed access.
“Coffee and cigarettes: modulation of high and low sensitivity α4β2 nicotinic acetylcholine receptors by n-MP, a biomarker of coffee consumption” by Roger L. Papke et al. Neuropharmacology
Coffee and cigarettes: modulation of high and low sensitivity α4β2 nicotinic acetylcholine receptors by n-MP, a biomarker of coffee consumption
Smokers report that they particularly appreciate coffee with their first cigarette of the day.
We investigated the effects of aqueous extracts (coffee) from green and roasted coffee beans using voltage clamp experiments on the activity of the nicotinic acetylcholine receptor (nAChR) subtypes of the human brain, expressed in terms of Xenopus oocytes, looking at complex brews, low molecular weight fractions (LMW) and specific compounds present in coffee.
When co-administered with PNU-120596, a positive allosteric modulator (PAM), the coffees stimulated currents of cells expressing α7 nAChR larger than ACh controls.
The PAM-dependent responses to green beans were three times greater than those to dark roast coffee, consistent with α7 receptor activation by choline, a component of coffee that is partially broken down during the roasting process.
Coffee was tested for both high sensitivity (HS) and low sensitivity (LS) forms of α4β2 nAChR, which are associated with nicotine addiction.
To varying degrees, these receptors were both activated and inhibited by the coffee and LMW extracts. We also examined the activity of nine small molecules present in coffee. Only two compounds, 1-methylpyridinium and 1-1-dimethylpiperidium, produced during the coffee bean roasting process, showed significant effects on nAChR.
The compounds were competitive antagonists of the HS 42 receptors, but were PAMs for LS 4β2 receptors. HS receptors in smokers are likely to gradually desensitize during a day of smoking, but may be hypersensitive in the morning if nicotine levels in the brain are low.
A smoker’s first cup of coffee can therefore balance the effects of the first cigarette of the day in the brain.