Dynorphin A (1-13): in vivo opioid antagonist actions and non-opioid anticonvulsant effects in the rat flurothyl test.
Dynorphin A (1-13) acutely elevated the seizure threshold (ST) to the convulsant flurothyl, and this action was not blocked by naloxone. Increases in ST were also observed following i.c.v. injections of the non-opioid fragment dynorphin A (3-13). Pretreatment with dynorphin A (1-13), but not dynorphin A (3-13), non-competitively blocked the anticonvulsant effect of the mu selective opioid DAGO. Furthermore, pretreatment with dynorphin A (1-13) antagonized the delta antagonist properties of naloxone or ICI 154,129 in this seizure model. Thus, in addition to its non-opioid anticonvulsant effects, dynorphin A (1-13) exhibits unique antagonist actions which appear to be specific for the active opioid fragment.
D000818:Animals; D000927:Anticonvulsants; D004399:Dynorphins / Q000494:pharmacology*; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D004745:Enkephalins / Q000627:therapeutic use; D005481:Flurothyl; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D012640:Seizures / Q000503:physiopathology*
D000927:Anticonvulsants; D004745:Enkephalins; D010446:Peptide Fragments; D020875:Enkephalin, Ala(2)-MePhe(4)-Gly(5)-; D009270:Naloxone; C026843:dynorphin (1-13); D004399:Dynorphins; C045478:dynorphin (3-13); D005481:Flurothyl