Effects of nicotine on thermal pain detection in humans.

Abstract

Pain detection threshold (latency in seconds) was repeatedly assessed by a standardized, computer-controlled radiant heat stimulus applied to the skin before and after nicotine intake in 3 studies of smokers and nonsmokers. Placebo or doses of nicotine corrected for body weight were administered by measured-dose nasal spray. Nicotine increased pain latency (i.e., decreased pain sensitivity) significantly in each study, although effects were modest and somewhat inconsistent. Nicotine had no effect on skin temperature at the site of stimulation, arguing against an indirect effect on nociception through peripheral cardiovascular changes. Overall, there were no significant differences as a result of smoking status, indicating that nicotine's influence on pain sensitivity is a "true" drug effect and is not due to withdrawal relief. These findings suggest that nicotine produces an antinociceptive effect in humans, but its relationship to nicotine reinforcement is unclear.

Tobacco Smoking Can Potentiate C-fiber Evoked Potentials in Human Brain

“…On the contrary, we recently found that A fiber pain-related laser evoked potentials (LEPs) were reduced by smoking (Miyazaki et al, submitted 2009). Since the degree of the amplitude reduction was in parallel with the plasma concentration of nicotine, the finding was in line with previous studies showing antinociceptive effects of nicotine in animals [5,6] and humans [7,8].…”

Smoking and Pain

“…109 Second, analgesic effects of nicotine may differ across experimental pain models (table 1). Although nicotine consistently increases pain thresholds in cold pressor tests, 9,11,13,110 results are inconsistent with heat 108,111,112 or electrical stimulation pain models. 10,12,[113][114][115] Finally, the effects of nicotine may depend on sex.…”

“…In general, nicotine administration via nasal spray or transdermal patches reduces pain sensitivity in both smokers and nonsmokers. 10,108 Smoking a cigarette decreases awareness of and increases tolerance to some experimental pain stimuli, 10,12,13 but these effects may involve additional substances in cigarette smoke, as they are attenuated when nicotine-depleted cigarettes are smoked. 9,11 Results from studies with humans are more difficult to interpret than are results from animal studies for several reasons.…”

Effects of Smoking Cessation on Pain in Older Adults

“…First, chronic exposure to nicotine may change the central nervous system (Mukhin et al, 2008;Sallette et al, 2005) such that pain perception is altered (Perkins et al, 1994;Silverstein, 1982). Second, smoking may worsen disease processes, such as osteoporosis, which may cause pain Glassman et al, 2000;Law & Hackshaw, 1997).…”

“…Several considerations may apply. In experimental humans and animal studies, smoking can have acute analgesic effects in subjects without chronic pain (Jamner et al, 1998;Perkins et al, 1994), which could favor pain exacerbation when exposure to smoke is eliminated. However, it is not known whether smoking a cigarette changes pain perception in smokers with chronic pain.…”