Dopamine manipulation limited to pre-exposure session is sufficient to modulate latent inhibition
-
1
Cadi Ayyad University, Biology, Morocco
-
2
Cadi Ayyad University, Morocco
Animals with a neonatal ventral hippocampal lesion develop abnormal behaviors during or after adolescence, suggesting that early insults can have delayed consequences. Both the amygdala and hippocampus are implicated in psychiatric disorders as autism, attention-deficit, hyperactivity, and schizophrenia. Disruption of latent inhibition (LI) has been proposed as a possible model of cognitive abnormalities that underlie positive symptoms of schizophrenia.
The present study was undertaken in order to test whether the latent inhibition (LI) is disrupted in postnatal lesioned rats using bilateral injection of Lidocaine into the ventral hippocampus.
A neonatal ventral-hippocampal lesion (nVH lesion) was made in 7 days old Sprague-dawley pups. Two groups were formed, the first one received Lidocaine (4μg/0.3μl) and the second was constituted by Sham operated control animals. At postnatal day 56, both groups were tested for social contact, locomotor activity in an open field to confirm the establishment of schizophrenia symptoms. The latent inhibition was studied using the conditioned taste aversion paradigm and after injection of D2 antagonist of dopamine receptors, Haloperidol (0.1 mg/kg) injected before pre-exposition phase (PE) sessions.
In behavioral study, we reported that the lesion of nVH induced several changes that mimic the schizophrenia symptoms. Indeed, at the pubertal age, animals showed a significant decrease in the number of social interactions and highly increase in the locomotor compared to controls.
Conditioned aversion taste showed that the nVH lesion significantly alters the latent inhibition which was more reduced compared to the control. However, we have shown that the injection of haloperidol, 45 min before each of pre-exposure session in lesioned animals can recover substantially the latent inhibition to values around those of controls.
Histological Nissl stained sections throughout the ventral hippocampus showed that the neonatal bilateral administration of Lidocaine caused some alterations, such as chromatin condensation, nucleolus loss, and cell shrinkage, but without glial proliferation as seen in several studies using Ibotenic acid.
Thus, these experiments demonstrated that nVH lesion using Lidocaine cause many behavioral changes related to Schizophrenia: Disruption of (LI), hyperactivity, anxiety and a decrease in social interactions between animals. Furthermore our results showed that injection of Haloperidol restricted only to the tree days of the pre-exposure phase is sufficient to facilitate LI of CTA.
Keywords:
Latente inhibition,
Schizophrenia,
Hippocampus,
pre-exposure,
Dopamine
Conference:
4th Conference of the Mediterrarnean Neuroscience Society, Istanbul, Türkiye, 30 Sep - 3 Oct, 2012.
Presentation Type:
Poster Presentation
Topic:
Abstracts
Citation:
Zakaria
O,
Saadia
B and
BENNIS
M
(2013). Dopamine manipulation limited to pre-exposure session is sufficient to modulate latent inhibition.
Conference Abstract:
4th Conference of the Mediterrarnean Neuroscience Society.
doi: 10.3389/conf.fnhum.2013.210.00074
Copyright:
The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers.
They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.
The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.
Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.
For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.
Received:
25 Jan 2013;
Published Online:
11 Apr 2013.
*
Correspondence:
Prof. Mohamed BENNIS, Cadi Ayyad University, Biology, Marrakech, Marrakech, 40000, Morocco, mbennis@ucam.ac.ma