Abstract
The influence of brain histamine (HA) on learning and memory is not well understood, although some reports indicate that HA improves memory consolidation. We have studied the effects of α-fluoromethylhistidine (FMH) (100 mg/Kg, i.p.), which reduced by 60–80% the concentration of hypothalamic HA, on rat locomotor activity (LA) and learning in several experimental conditions in a computerized system. FMH reduced LA in an open field paradigm (OFP) 3h after injection and tended to inhibit motor habituation after a 3-day trial. In a maze paradigm (MP), where the animals had to learn to avoid a foot-shock (1 mA), FMH reduced LA, rearing (2F), and jumping activity (JA). The peripheral administration of HA to control-trained rats reduced a learning index (N/Sts ratio) by 50%. According to these results, FMH diminished LA, 2F, and JA with no effect on habituation in MP. These observations might indicate that a moderate reduction in the levels of brain HA might enhance attention in solving visuo-spatial tasks under stressful stimuli.
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Cacabelos, R., Alvarez, X.A. Histidine decarboxylase inhibition induced by α-fluoromethylhistidine provokes learning-related hypokinetic activity. Agents and Actions 33, 131–134 (1991). https://doi.org/10.1007/BF01993147
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DOI: https://doi.org/10.1007/BF01993147