Role of H1 cerebellar histaminergic receptor on memory consolidation of inhibitory avoidance

Abstract

Histamine is a neurotransmitter in the central nervous system. The cell bodies of histaminergic neurons are present in the posterior hypothalamus in the tuberomammillary nucleus. Histamine via H1 receptor excites neurons in several brain areas. Our recent study showed that histamine microinjected into the cerebellar vermis facilitated memory consolidation of inhibitory avoidance. The aim of this study is to verify if this effect can be reversed with H1 receptor antagonist chlorpheniramine. Swiss albino mice weighed between 25 and 35 g will be implanted with guide cannulae. Three days after surgery, the inhibitory avoidance test will be performed in two consecutive days, training and test. Immediately after training session, animals will receive microinjection of saline or chlorpheniramine (0.16 nmol/0.1 microliter) in the cerebellar vermis, and 5 minutes after microinjection of histamine (1.36 nmol/0.1 microliter). Twenty-four hours later, retention test will be performed to evaluate memory consolidation. The experiments will be recorded to measure the latency of mice. The histology will verify the injections sites. The data will be analyzed using one-way Analysis of Variance (ANOVA) and Duncan´s tests. (AU)