The NMDA-receptor antagonist dizocilpine (MK-801) suppresses the memory facilitatory action of thyrotropin-releasing hormone.
Thyrotropin-releasing hormone (TRH) has been shown to improve memory both in animal amnesia models and in humans. In an earlier study we have found that respiratory stimulant action of TRH is mediated through the N-methyl-D-aspartate (NMDA) receptors. Since brain NMDA receptors are implicated in neuronal plasticity, we have investigated whether the non-competitive NMDA antagonist dizocilpine antagonizes the memory-facilitatory action of TRH. TRH (5 mg/kg i.p.) increased passive avoidance scores in the rats in both memory retention and retrieval tests. Dizocilpine (0.2 mg/kg i.p.) caused no significant performance changes. However, it completely blocked the improvement of retention caused by TRH and reversed its effect on retrieval. We conclude that the facilitatory effect of TRH on avoidance retention and retrieval may be mediated by NMDA receptors.
Kasparov
S A
SA
Department of Pharmacology, Moscow Sechenov Medical Academy, Russia.
Chizh
B A
BA
D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D016291:Dizocilpine Maleate / Q000494:pharmacology*; D008297:Male; D008568:Memory / Q000187:drug effects*; D009619:Nociceptors / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors*; D013973:Thyrotropin-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000494:pharmacology
D016194:Receptors, N-Methyl-D-Aspartate; D013973:Thyrotropin-Releasing Hormone; D016291:Dizocilpine Maleate