title: Histamine acting on the basolateral amygdala reverts the impairment of aversive memory of rats submitted to neonatal maternal deprivation.
abstract: Recent findings suggest a role of brain histamine in the regulation of memory consolidation, particularly in one-trial inhibitory avoidance (IA) learning and that disruption in the mother infant relationship i.e. maternal deprivation induces cognitive deficits. We investigate whether histamine itself, and histaminergic compounds given into the basolateral amygdala (BLA) immediately post-training can affect retention (24 h after training) of one-trial (IA) in rats submitted to early postnatal maternal deprivation. In all cases, deprived (Dep) animals had lower retention scores than non-deprived controls (N-dep). Histamine induced memory enhancement on its own in N-dep animals and was able to overcome the deleterious effect of Dep. The effects by SKF-91488 is similar to histamine. The H3 agonist, imetit mimetized the enhancing effects of histamine; neither agonist H1 pyridylethylamine nor the H2 dimaprit had any effect. Ranitidine and thioperamide (50 nmol) co-infused with histamine (10 nmol) fully blocked the restorative effect of histamine on retention in Dep animals. Thioperamide, in addition, blocked the enhancing effect of histamine on memory of the N-dep animals as well. None of the drugs used given into BLA had any effect on open-field or elevated plus-maze behavior in N-dep or Dep rats. Our results are limited to experimental design in rats. Extrapolation i.e. in humans requires further experimentations. The present results suggest that the memory deficit induced by early postnatal maternal deprivation in rats may at least in part be due to an impairment of histamine H3 receptor-mediated mediated mechanisms in the BLA.
authors.affiliation: Centro de Memória, Instituto do Cérebro, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga 6690, 2(o) andar, Porto Alegre RS 90610-000, Brazil; Instituto Nacional de Neurociência Translacional, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Avenida Ipiranga 6690, 2(o) andar, Porto Alegre RS 90610-000, Brazil; Departamento de Fisiologia, Instituto de Ciências Básicas da Saúde (ICBS), Universidade Federal do Rio Grande do Sul (UFGS), Rua Sarmento Leite, 500, Porto Alegre RS 9050-170, Brazil.
authors.forename: Fernando
authors.initials: F
authors.lastname: Benetti
authors.affiliation: Universidade Federal de Ciências da Saúde de Porto Alegre, RS 90050-170, Brazil.
authors.forename: Clarice Kras Borges
authors.initials: CK
authors.lastname: da Silveira
authors.affiliation: Centro de Memória, Instituto do Cérebro, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga 6690, 2(o) andar, Porto Alegre RS 90610-000, Brazil; Instituto Nacional de Neurociência Translacional, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Avenida Ipiranga 6690, 2(o) andar, Porto Alegre RS 90610-000, Brazil.
authors.forename: Jessica
authors.initials: J
authors.lastname: Rosa
authors.affiliation: Centro de Memória, Instituto do Cérebro, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Avenida Ipiranga 6690, 2(o) andar, Porto Alegre RS 90610-000, Brazil; Instituto Nacional de Neurociência Translacional, Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Avenida Ipiranga 6690, 2(o) andar, Porto Alegre RS 90610-000, Brazil. Electronic address: izquier@terra.com.br.
authors.forename: Ivan
authors.initials: I
authors.lastname: Izquierdo
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001362:Avoidance Learning / Q000187:drug effects; D066272:Basolateral Nuclear Complex / Q000187:drug effects* / Q000378:metabolism*; D017259:Dimaprit / Q000031:analogs & derivatives / Q000494:pharmacology; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D005106:Exploratory Behavior / Q000187:drug effects; D005260:Female; D006632:Histamine / Q000378:metabolism / Q000494:pharmacology*; D017442:Histamine Agonists / Q000494:pharmacology; D006633:Histamine Antagonists / Q000494:pharmacology; D007266:Inhibition, Psychological; D008297:Male; D008426:Maternal Deprivation; D018782:Maze Learning / Q000187:drug effects; D008569:Memory Disorders / Q000139:chemically induced* / Q000473:pathology*; D011247:Pregnancy; D051381:Rats; D017208:Rats, Wistar
chemical_list: D017442:Histamine Agonists; D006633:Histamine Antagonists; C024535:SK&F 91488; D006632:Histamine; D017259:Dimaprit
keywords: BLA; Histamine; Imetit; Inhibitory avoidance; Maternal deprivation; Thioperamide