Levorphanol and swim stress-induced analgesia in selectively bred mice: evidence for genetic commonalities.
Two independent selective breeding programs have developed divergent lines of mice expressing either high and low swim stress-induced analgesia (HA/LA lines; Jastrzebiec, Poland) or high and low levorphanol analgesia (HAR/LAR lines; Portland, OR). In the present study, mice from both programs were tested for both levorphanol analgesia (2 mg/kg) and an opioid-mediated swim stress-induced analgesia (3 min swimming in 32 degrees C water) in the hot-plate test. Mice selected for high and low levorphanol analgesia displayed high and low swim stress-induced analgesia, respectively; mice selected for high and low swim stress-induced analgesia displayed high and low levorphanol analgesia, respectively. This pattern of correlated responses suggests a high degree of common genetic determination in opiate and swim stress-induced analgesia. These findings also suggest that individual differences in analgesic responsiveness to opiate drugs result from genetically determined individual differences in endogenous pain inhibitory mechanisms.
Marek
P
P
Department of Psychology, University of California, Los Angeles 90024.
Mogil
J S
JS
Belknap
J K
JK
Sadowski
B
B
Liebeskind
J C
JC
D000698:Analgesia; D000818:Animals; D005260:Female; D006358:Hot Temperature; D007206:Individuality; D007981:Levorphanol / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D017288:Pain Threshold / Q000187:drug effects; D013045:Species Specificity; D013315:Stress, Psychological / Q000235:genetics* / Q000523:psychology; D013550:Swimming
D007981:Levorphanol