Dataset Information

M4 muscarinic receptor knockout mice display abnormal social behavior and decreased prepulse inhibition.

ABSTRACT:

Background

In the central nervous system (CNS), the muscarinic system plays key roles in learning and memory, as well as in the regulation of many sensory, motor, and autonomic processes, and is thought to be involved in the pathophysiology of several major diseases of the CNS, such as Alzheimer's disease, depression, and schizophrenia. Previous studies reveal that M4 muscarinic receptor knockout (M4R KO) mice displayed an increase in basal locomotor activity, an increase in sensitivity to the prepulse inhibition (PPI)-disrupting effect of psychotomimetics, and normal basal PPI. However, other behaviorally significant roles of M4R remain unclear.

Results

In this study, to further investigate precise functional roles of M4R in the CNS, M4R KO mice were subjected to a battery of behavioral tests. M4R KO mice showed no significant impairments in nociception, neuromuscular strength, or motor coordination/learning. In open field, light/dark transition, and social interaction tests, consistent with previous studies, M4R KO mice displayed enhanced locomotor activity compared to their wild-type littermates. In the open field test, M4R KO mice exhibited novelty-induced locomotor hyperactivity. In the social interaction test, contacts between pairs of M4R KO mice lasted shorter than those of wild-type mice. In the sensorimotor gating test, M4R KO mice showed a decrease in PPI, whereas in the startle response test, in contrast to a previous study, M4R KO mice demonstrated normal startle response. M4R KO mice also displayed normal performance in the Morris water maze test.

Conclusions

These findings indicate that M4R is involved in regulation of locomotor activity, social behavior, and sensorimotor gating in mice. Together with decreased PPI, abnormal social behavior, which was newly identified in the present study, may represent a behavioral abnormality related to psychiatric disorders including schizophrenia.

SUBMITTER: Koshimizu H

PROVIDER: S-EPMC3361477 | biostudies-literature | 2012 Apr

REPOSITORIES: biostudies-literature

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Publications

M4 muscarinic receptor knockout mice display abnormal social behavior and decreased prepulse inhibition.

Koshimizu Hisatsugu H Leiter Lorene M LM Miyakawa Tsuyoshi T

Molecular brain 20120402

<h4>Background</h4>In the central nervous system (CNS), the muscarinic system plays key roles in learning and memory, as well as in the regulation of many sensory, motor, and autonomic processes, and is thought to be involved in the pathophysiology of several major diseases of the CNS, such as Alzheimer's disease, depression, and schizophrenia. Previous studies reveal that M4 muscarinic receptor knockout (M4R KO) mice displayed an increase in basal locomotor activity, an increase in sensitivity ...[more]

PMID: 22463818

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Project description:BackgroundRASopathies are a group of disorders that result from mutations in genes coding for proteins involved in regulating the Ras-MAPK signaling pathway, and have an increased incidence of autism spectrum disorder (ASD). Legius syndrome is a rare RASopathy caused by loss-of-function mutations in the SPRED1 gene. The patient phenotype is similar to, but milder than, Neurofibromatosis type 1-another RASopathy caused by loss-of-function mutations in the NF1 gene. RASopathies exhibit increased activation of Ras-MAPK signaling and commonly manifest with cognitive impairments and ASD. Here, we investigated if a Spred1-/- mouse model for Legius syndrome recapitulates ASD-like symptoms, and whether targeting the Ras-MAPK pathway has therapeutic potential in this RASopathy mouse model.MethodsWe investigated social and communicative behaviors in Spred1-/- mice and probed therapeutic mechanisms underlying the observed behavioral phenotypes by pharmacological targeting of the Ras-MAPK pathway with the MEK inhibitor PD325901.ResultsSpred1-/- mice have robust increases in social dominance in the automated tube test and reduced adult ultrasonic vocalizations during social communication. Neonatal ultrasonic vocalization was also altered, with significant differences in spectral properties. Spred1-/- mice also exhibit impaired nesting behavior. Acute MEK inhibitor treatment in adulthood with PD325901 reversed the enhanced social dominance in Spred1-/- mice to normal levels, and improved nesting behavior in adult Spred1-/- mice.LimitationsThis study used an acute treatment protocol to administer the drug. It is not known what the effects of longer-term treatment would be on behavior. Further studies titrating the lowest dose of this drug that is required to alter Spred1-/- social behavior are still required. Finally, our findings are in a homozygous mouse model, whereas patients carry heterozygous mutations. These factors should be considered before any translational conclusions are drawn.ConclusionsThese results demonstrate for the first time that social behavior phenotypes in a mouse model for RASopathies (Spred1-/-) can be acutely reversed. This highlights a key role for Ras-MAPK dysregulation in mediating social behavior phenotypes in mouse models for ASD, suggesting that proper regulation of Ras-MAPK signaling is important for social behavior.

Dataset Information

M4 muscarinic receptor knockout mice display abnormal social behavior and decreased prepulse inhibition.

Background

Results

Conclusions

Publications

M4 muscarinic receptor knockout mice display abnormal social behavior and decreased prepulse inhibition.

Similar Datasets

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