Nicotine-Induced Antinociception in Male and Female Sprague-Dawley Rats
Abstract
Nicotine is a key pharmacologically-active ingredient in tobacco that has cognitive and behavioral effects, including antinociception. The present research examined effects of nicotine as an antinociceptive agent in male and female Sprague-Dawley rats. Nicotine was administered subcutaneously (SC) to 145 male and female Sprague-Dawley rats. Behavioral measures of nociception included tail-flick, hot-plate, and cold-flick. The Formalin test, a model for persistent pain, was used to examine nicotine-induced antinociception. After antinociceptive testing, animals were sacrificed and blood was collected and assayed for plasma 17-beta- estradiol (in females), testosterone (in males), plasma nicotine and cotinine, brain and spinal cord nicotine and cotinine levels. On the tail-flick measure, 8 and 12 minutes after drug injection, males increased latencies to respond after receiving 0.1 or 1.0 mg/kg nicotine, whereas females increased latencies to respond only after receiving 1.0 mg/kg nicotine. Gender differences in pain responses in the absence of nicotine may have contributed to the gender differences in nicotine-induced antinociception. Nicotine was antinociceptive for both sexes on hot-plate and on cold-flick tests. On the Formalin Test 20 and 25 minute after nicotine injection, 1.0 mg/kg nicotine was significantly antinociceptive for females but not for males. Thirty minutes after nicotine injection, 1.0 mg/kg nicotine was significantly antinociceptive for males but not females. Estrus cycle stage was significantly correlated with the cold-flick measure such that females in diestrus stage had longer latencies than females in other estrus stages. 17-beta-estradiol and testosterone did not significantly correlate with nicotine-induced antinociception.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 21, 1999
- Accession Number
- ADA444183
Entities
People
- Nathaniel Apatov
Organizations
- Uniformed Services University of the Health Sciences