Potentiation of swim analgesia by D-amino acids in mice is genotype dependent.
The effect of combined treatment with 125 mg/kg of D-phenylalanine plus 125 mg/kg of D-leucine (IP) on magnitude and duration of analgesia caused by 3 min swim at 20 degrees C was studied in mouse lines selectively bred for 20 generations toward high and low level of stress-induced analgesia. The D-amino acids administered 30 min prior to swimming increased postswim tail-flick latencies and prolonged antinociception more in the high analgesia line (HA) than in concomitantly bred unselected controls, but were not effective in the low analgesia line (LA). The potentiation of swim analgesia by D-amino acids was prevented by simultaneous administration of 1 mg/kg of naloxone hydrochloride which, given alone, antagonized the analgesia more in the HA line than in controls, but not in the LA line. The results are interpreted in terms of genetic differentiation of opioidergic transmission in the selectively bred mouse lines.
Panocka
I
I
Department of Behavioral Physiology, Polish Academy of Sciences, Mroków.
Sadowski
B
B
D000596:Amino Acids / Q000494:pharmacology*; D000698:Analgesia; D000818:Animals; D005260:Female; D005838:Genotype; D007930:Leucine / Q000494:pharmacology; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009270:Naloxone / Q000494:pharmacology; D010147:Pain Measurement; D010649:Phenylalanine / Q000494:pharmacology; D011930:Reaction Time / Q000187:drug effects; D013550:Swimming
D000596:Amino Acids; D009270:Naloxone; D010649:Phenylalanine; D007930:Leucine