Analgesic effects of dynorphin-A and morphine in mice.
To investigate whether or not dynorphin-A is analgesic, the effect of this peptide was tested in comparison with that of morphine in mice. Dynorphin-A produced a potent analgesic effect in the acetic acid writhing and tail pinch tests, but a weak effect in the tail flick test when given by intracerebroventricular injection. In contrast, morphine caused a potent analgesia in all the tests. Dynorphin-A was more effective when given by intrathecal injection than by intracerebroventricular injection, whereas morphine was equipotent by both injection routes. The results suggest that dynorphin-A is analgesic and that its analgesia may be differentiated from that of morphine.
Nakazawa
T
T
Ikeda
M
M
Kaneko
T
T
Yamatsu
K
K
D000700:Analgesics; D000818:Animals; D004399:Dynorphins / Q000008:administration & dosage / Q000494:pharmacology*; D007276:Injections, Intraventricular; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D009020:Morphine / Q000008:administration & dosage / Q000494:pharmacology*; D010146:Pain / Q000503:physiopathology; D010446:Peptide Fragments / Q000008:administration & dosage / Q000494:pharmacology
D000700:Analgesics; D010446:Peptide Fragments; C026843:dynorphin (1-13); D004399:Dynorphins; D009020:Morphine