Influence of dynorphin A (1-13) and dynorphin A (1-10) amide on stress-induced analgesia.
Dynorphin A (1-13) and its analog dynorphin A (1-10) amide were applied intracerebroventricularly in male ICR mice. Both dynorphins did not reveal any analgesic activity in tail-flick test under normal (non-stressed) conditions. However, in combination with stress (forced swimming or whole body vibration) both dynorphins prolonged tail-flick latencies when compared with stressed saline controls. Naloxone inhibited the effect of dynorphins in forced swimming test. Neither dynorphin A (1-13) nor dynorphin A (1-10) amide increased tail-flick latencies when combined with weak immobilization stress. Our results suggest that the analgesic effects of dynorphins are potentiated by strong stressors.
Starec
M
M
Institute of Pharmacology, Third Faculty of Medicine, Charles University, Prague, Czech Republic.
Rosina
J
J
Málek
J
J
Krsiak
M
M
D000698:Analgesia; D000701:Analgesics, Opioid / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D000818:Animals; D004399:Dynorphins / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D007101:Immersion; D007103:Immobilization; D007276:Injections, Intraventricular; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D010147:Pain Measurement / Q000187:drug effects; D010446:Peptide Fragments / Q000008:administration & dosage / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D013315:Stress, Psychological / Q000523:psychology*; D013550:Swimming; D014732:Vibration / Q000009:adverse effects
D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D010446:Peptide Fragments; D009270:Naloxone; C026843:dynorphin (1-13); D004399:Dynorphins; C039666:dynorphin amide (1-10)