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.
Department of Psychology, University of California, Los Angeles 90024.
P
P
Marek
J S
JS
Mogil
J K
JK
Belknap
B
B
Sadowski
J C
JC
Liebeskind
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