Age-related differences in forced walking stress-induced analgesia in mice.
We investigated the effects of aging on forced walking stress-induced analgesia using a formalin-induced paw licking test in male mice. Exposure to forced walking stress for 6 h showed forced walking stress-induced analgesia in all mice aged 4, 24 and 48 weeks in the second phase (10-30 min), but not in the first phase (0-10 min). In the second phase, the degree of stress-induced analgesia was age-dependent (4 > 24 > 48 weeks). LY-235959, a competitive N-methyl-D-aspartate (NMDA) receptor antagonist, blocked forced walking stress-induced analgesia in mice aged 4 and 24 weeks, but not in those aged 48 weeks. Naloxone did not antagonize forced walking stress-induced analgesia in mice in any of the age groups. The present study suggests that the degree of forced walking stress-induced analgesia depends on the age of mice and confirms previous findings that forced walking stress-induced analgesia is involved in the nonopioid system via NMDA receptors.
Onodera
K
K
Department of Dental Pharmacology, Okayama University Graduate School of Medicine and Dentistry, 5-1, Shikata-cho 2-chome, Okayama, 700-8525, Japan. onoderak@md.okayama-u.ac.jp
Sakurada
S
S
Furuta
S
S
Yonezawa
A
A
Hayashi
T
T
Honma
I
I
Miyazaki
S
S
D000375:Aging / Q000502:physiology*; D000698:Analgesia; D000818:Animals; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005557:Formaldehyde; D007546:Isoquinolines / Q000494:pharmacology; D008297:Male; D051379:Mice; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D013315:Stress, Psychological / Q000503:physiopathology*; D016138:Walking / Q000502:physiology* / Q000523:psychology*
D018691:Excitatory Amino Acid Antagonists; D007546:Isoquinolines; D009292:Narcotic Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D005557:Formaldehyde; D009270:Naloxone; C088643:LY 235959