Dorsal hippocampal microinjection of chlorpheniramine reverses the anxiolytic-like effects of l-histidine and impairs emotional memory in XXXX .

@entity19 @entity2414 @entity148 @entity146
UNASSIGNED: Several findings have pointed to the role of histaminergic neurotransmission in the modulation of @entity148 -like @entity146 . The elevated plus-maze (EPM) test has been widely used to investigate the process of @entity148 and also has been used to investigate the process of learning and memory. Visual cues are relevant to the formation of spatial maps, and as the hippocampus is involved in this task, experiment 1 explored this issue. Experiment 2 investigated the effects of intraperitoneal (i.p.) injections of l-histidine (LH, a precursor of histamine) and of intra-dorsal hippocampus (intra-DH) injections of chlorpheniramine (CPA, an H1 receptor antagonist) on @entity148 in @entity19 re-exposed to the EPM. @entity19 received saline (SAL) or LH i.p. and SAL or CPA (0.016, 0.052, and 0.16nmol/0.1 l) intra-DH prior to Trial 1 (T1) and Trial 2 (T2). No significant changes were observed in the number of enclosed-arm entries (EAE) in T1, an EPM index of general exploratory activity. LH had an anxiolytic-like effect that was reversed by intra-DH injections of CPA. T2 versus T1 analysis revealed that only the lower dose of CPA resulted in @entity2414 . Combined injections of LH and CPA revealed that higher doses of CPA impair emotional memory. Taken together, these results suggest that LH and H1 receptors present in the dorsal hippocampus are involved in @entity148 -related @entity146 in @entity19 submitted to EPM.
