[The improvement of memory retention and retrieval of a novel vasopressin fragment analog NC-1900].
The effects of a novel vasopressin (AVP) fragment analog NC-1900 (pGlu-Asn-Ser-Pro-Arg-Gly-NH2 acetate) were studied on the performance of memory retention and retrieval in mice. NC-1900 of one time application of 1 hr after the acquired trial (electric shock) extended the latent period of passive avoidance task 21 days after the acquired trial. Though the extended response was also recognized with AVP4-9, the potency was approx. 1/1000 of NC-1900. The potentiation wasn't recognized with vasopressin. NC-1900 showed a significantly high correct answer after 21 days after the last trial in the search task. While, V1 antagonist Pmp1-Tyr (Me)2-AVP shortened the latent period of passive avoidance task. On the other hand, NC-1900 extended the reaction latency 21 days after the acquired trial by the application 1 hr before the retention trial. Though this improvement of memory retrieval was recognized with vasopressin and AVP4-9, the potency was 1/100-1/1000. NC-1900 improved the retrieval 24 h after the CO2 exposure. V1 antagonists Pmp1-Tyr-Me2-AVP or Deamino-Pen1, O-Me-Tyr2-AVP, and PMA had no effects on the retrieval 21 days after the acquired trial. These results suggest that NC-1900 may have the memory retention and retrieval potentiating action, and that phospholipase C-protein kinase C system may be involved in the former action, and the latter action not be involved.
Sato
Tomoaki
T
Department of Pharmacology, Kagoshima University Dental School, Sakuragaoka 890-8544, Japan.
Tanaka
Koh-ichi
K
Ohnishi
Yoshiko
Y
Teramoto
Toyonori
T
Hirate
Kenji
K
Nishikawa
Takashige
T
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D008297:Male; D008568:Memory / Q000187:drug effects*; D051379:Mice; D009842:Oligopeptides / Q000008:administration & dosage / Q000494:pharmacology*; D011493:Protein Kinase C / Q000502:physiology; D011761:Pyrrolidonecarboxylic Acid / Q000031:analogs & derivatives; D011930:Reaction Time; D021641:Recognition, Psychology / Q000187:drug effects*; D012153:Retention, Psychology / Q000187:drug effects*; D013268:Stimulation, Chemical; D013997:Time Factors; D010738:Type C Phospholipases / Q000502:physiology
C115056:NC 1900; D009842:Oligopeptides; D011493:Protein Kinase C; D010738:Type C Phospholipases; D011761:Pyrrolidonecarboxylic Acid