Intrahippocampal GMP administration improves inhibitory avoidance performance through GABAergic and glutamatergic mechanisms in rats

Abstract

Guanidino compounds play specific physiological and pathological roles in the central nervous system. We investigated the effect of an intrahippocampal infusion of GMP (a guanidino compound) administered immediately post-training on the inhibitory avoidance learning paradigm in rats. Bilateral intrahippocampal micro-injection of GMP (0-30 nmol) caused a dose-dependent increase in test step-down latencies which was completely reversed by intrahippocampal co-administration of muscimol or baclofen (GABA agonists) or preadministration (15 min pre-training, i.p.) of MK-801 (an NMDA antagonist). These results provide evidence for a participation of GABA and NMDA receptors in the GMP-induced increase in the test step-down latencies.

Tadalafil enhances working memory, and reduces hippocampal oxidative stress in both young and aged mice

“…The administration of cGMP analogs into the hippocampus (injection) immediately after training has shown improved memory performance in the object recognition (Prickaerts et al, 2002) and passive avoidance test (Rubin et al, 1997). Several mechanisms of action could explain how cGMP exerts the increased memory processes.…”

Nitric oxide is involved in the memory facilitation induced by spermidine in rats

“…This test was carried out to identify motor disabilities, which might influence inhibitory avoidance performance at testing. Injection placements were histologically verified, as described elsewhere (Rubin et al 1997). Only data from the animals with correct cannula placement were analyzed.…”

Spermidine-induced improvement of reconsolidation of memory involves calcium-dependent protein kinase in rats

“…and were implanted with two 27-gauge guide cannulae placed 1-mm above the CA1 region of the dorsal hippocampus at the following coordinates: A ¼ 4.0 mm; L ¼ 3.0 mm; and V ¼ 2.0 mm (Paxinos and Watson 1986). Placement of injections was histologically verified, as described elsewhere (Rubin et al 1997). A total of 222 animals were subjected to stereotaxic surgery.…”