The NMDA receptor antagonist MK-801 fails to impair long-term recognition memory in mice when the state-dependency of memory is controlled

Abstract

Highlights The role of NMDA receptors in encoding of object memory was assessed. A retention interval of 24 h was used. When state-dependency was controlled MK-801 failed to impair memory.

Nigella Sativa Supplementations Attenuate Recognition Memory and Cellular Morphometric Impairments Induced by Toluene Administration in Mice

“…Prolonged exposure to high doses of air freshener containing toluene caused significant memory dysfunction in mice, while no changes were observed in lower doses (Umukoro et al 2021). As opposed to the present study, the study by Chan et al (2019) administered toluene in mice 30 min before the NOR test. Rats subjected to the NOR test 30 min after exposed to toluene also showed significant reduction in the recognition index (Huerta-Rivas et al 2012).…”

“…The doses of NSS, NSO, and TQ used in this study were literature based (Al-Nailey 2010; Baghcheghi et al 2018;Cheema et al 2018). The toluene dosage used in this study was carefully selected based on our preliminary tests conducted prior to this study, and well aligned with previous studies (Chan et al 2019;Seo et al 2010). Intraperitoneal injection of toluene has been documented to cause the same behavioral symptoms as inhalation (Chan et al 2019;Hsieh et al 2020;Lee et al 2020;Seo et al 2010;Wu et al 2018) and it is generally easier to administer.…”

“…The tendency of decreased memory performance in toluene treated subjects might be due to the effects of toluene on neurotransmitters involved in memory. Prominent reduction in the expression level of NR1 and NR2 messenger ribonucleic acid (mRNA) after a single toluene exposure ) and a destructive effect on short and long-term memory performance in the NOR test in rats treated with MK801, a noncompetitive NMDA receptor antagonist (Chan et al 2019) were observed. NMDA receptor converts certain neuronal activities into structural and functional changes of the synapse, which are essential for memory formation (Liu et al 2019).…”

MK-801 and cognitive functions: Investigating the behavioral effects of a non-competitive NMDA receptor antagonist

“…Furthermore, authors pinpointed that observed memory consolidation facilitation may be somehow associated with the NMRI strain (M. Nilsson et al 2007). Conversely, the research on female C57BL/6 J mice argued against the hypothesis and examined whether MK-801, instead of impairing memory encoding, may act state-dependently and whether the change in a drug-state causes impairments (M. Chan et al 2019). In the first part of this study, animals received either MK-801 (0.01 mg/kg, ip) or vehicle before the exposure phase on day 1, and then 24 h later, they were administered with either the same or different substance prior to the test phase.…”

“…It was also reported that MK-801 induced locomotor hyperactivity in a higher dose. Moreover, according to the authors, the period between the exposure and test phases (1 day), as well as the lack of memory deficits, may suggest that MK-801 impaired short-term but not long-term recognition memory (M. Chan et al 2019). However, comparing these contrasting results is challenging due to the fact that this study was conducted on female mice, and the potential influence of the estrus cycle phase on the MK-801-induced effects cannot be overlooked.…”