Chronic nicotine reverses age-associated increases in tail-flick latency and anxiety in rats.
The chronic consumption of low doses of nicotine in drinking water for two years consistently increased the sensitivity of rats to a nociceptive thermal stimulus (tail-flick test), but reduced aversiveness in the elevated plus-maze test, relative to the responses of age-matched controls in these tests. The responses of aged nicotine-consuming rats were indistinguishable from those of young adult rats that did not receive nicotine. To determine whether these effects were due to a nicotine-induced retardation of age-related changes, young adult rats were similarly treated with nicotine for three months and similar changes in the tail-flick latency and performance in the plus-maze test were observed during nicotine consumption. These changes were reversed following withdrawal from nicotine. It is concluded that the maintenance of circulating low levels of nicotine (and/or its metabolites) increased the nociceptive sensitivity of the rats and reduced their aversions in the plus-maze test regardless of their age.
Onaivi
E S
ES
Laboratory of Neurosciences, Pennington Biomedical Research Center, Baton Rouge, LA 70808.
Payne
S
S
Brock
J W
JW
Hamdi
A
A
Faroouqui
S
S
Prasad
C
C
D000375:Aging / Q000187:drug effects* / Q000502:physiology*; D000818:Animals; D001007:Anxiety / Q000188:drug therapy*; D001522:Behavior, Animal / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D007837:Latency Period, Psychological; D008297:Male; D009538:Nicotine / Q000494:pharmacology*; D010147:Pain Measurement / Q000187:drug effects*; D017288:Pain Threshold / Q000187:drug effects; D051381:Rats; D011916:Rats, Inbred F344; D013997:Time Factors
D009538:Nicotine