Posters

Presenting Author

Jatziry Luna

Presentation Type

Poster

Discipline Track

Biomedical Science

Abstract Type

Research/Clinical

Abstract

Background/ Purpose: Gamma-aminobutyric acid (GABA) is an amino acid that serves as the central nervous system’s (CNS) main inhibitory neurotransmitter. By inhibiting nerve transmission, it works to lower neuronal excitability. Altered GABA levels have been associated with a variety of psychiatric disorders, for example Epilepsies, Parkinson’s Disease, and Schizophrenia. Perineuronal nets (PNN) are extracellular molecules that are released by neurons and glial cells that modulate many neuronal and glial functions by encapsulating the inhibitory cells and neurites. Altered PNN levels serve as a potential trigger to synaptic imbalance. The purpose of this study is to quantify and analyze the presence, change in number, and area difference of GAD67 and Lectin in the brain of the Monodelphis domestica.

Methods: Two Monodelphis domestica were transcardially perfused with 4% paraformaldehyde and brains were collected and sliced at a thickness of 35 µm. An antibody for Glutamic Acid Decarboxylase (GAD_67) was used to identify GABAergic neurons and Lectin to identify the Perineuronal Nets, following the ABC-DAB method of immunohistochemistry. The criteria for identifying GAD-positive neurons and PNNs include presence of a dark brown reaction within the perikaryal cytoplasm. Using Image J software and stereological methods, midbrain sections targeting the Superior Colliculus Sensory and Motor and Substantia Nigra were used to compare the number of GABA cells and PNNs that were present. Moreover, a t-test and an ANOVA test were used to determine whether there was a statistically significant difference between the areas of the brain regions in focus. The average areas were obtained from 10 neurons for the GAD67 neurons antibody and Lectin in 4 different brain figures.

Results: GAD67 antibody and Lectin were both used to identify GABAergic neurons and PNNs, respectively. GAD67 neurons were smaller and had a less clearly defined cell body and nucleus than PNNs. Based on preliminary quantification of GAD67 neurons, the number of GAD67 neurons in the Superior Colliculus and the Substantia Nigra were significantly higher in animals under a social stimulus than the control group.

Conclusion: Our findings support the relevant literature regarding the way in which GAD67 and PNNs are expressed. By assessing the change in number and area difference in various regions of the brain, our recent findings will contribute to the use of Monodelphis as a model for neurological illnesses. Furthermore, we plan to relate our findings between GABAergic neurons and PNNs to hypothesize a connection between neural morphometry and connectivity and establish a relationship (or lack of relationship) between them.

Academic/Professional Position

Undergraduate

Mentor/PI Department

Office of Human Genetics

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Gamma-aminobutyric acid (GABA) Neurons and Perineuronal Nets (PNN) in the Monodelphis domestica and Relevance to Psychiatric Disorders

Background/ Purpose: Gamma-aminobutyric acid (GABA) is an amino acid that serves as the central nervous system’s (CNS) main inhibitory neurotransmitter. By inhibiting nerve transmission, it works to lower neuronal excitability. Altered GABA levels have been associated with a variety of psychiatric disorders, for example Epilepsies, Parkinson’s Disease, and Schizophrenia. Perineuronal nets (PNN) are extracellular molecules that are released by neurons and glial cells that modulate many neuronal and glial functions by encapsulating the inhibitory cells and neurites. Altered PNN levels serve as a potential trigger to synaptic imbalance. The purpose of this study is to quantify and analyze the presence, change in number, and area difference of GAD67 and Lectin in the brain of the Monodelphis domestica.

Methods: Two Monodelphis domestica were transcardially perfused with 4% paraformaldehyde and brains were collected and sliced at a thickness of 35 µm. An antibody for Glutamic Acid Decarboxylase (GAD_67) was used to identify GABAergic neurons and Lectin to identify the Perineuronal Nets, following the ABC-DAB method of immunohistochemistry. The criteria for identifying GAD-positive neurons and PNNs include presence of a dark brown reaction within the perikaryal cytoplasm. Using Image J software and stereological methods, midbrain sections targeting the Superior Colliculus Sensory and Motor and Substantia Nigra were used to compare the number of GABA cells and PNNs that were present. Moreover, a t-test and an ANOVA test were used to determine whether there was a statistically significant difference between the areas of the brain regions in focus. The average areas were obtained from 10 neurons for the GAD67 neurons antibody and Lectin in 4 different brain figures.

Results: GAD67 antibody and Lectin were both used to identify GABAergic neurons and PNNs, respectively. GAD67 neurons were smaller and had a less clearly defined cell body and nucleus than PNNs. Based on preliminary quantification of GAD67 neurons, the number of GAD67 neurons in the Superior Colliculus and the Substantia Nigra were significantly higher in animals under a social stimulus than the control group.

Conclusion: Our findings support the relevant literature regarding the way in which GAD67 and PNNs are expressed. By assessing the change in number and area difference in various regions of the brain, our recent findings will contribute to the use of Monodelphis as a model for neurological illnesses. Furthermore, we plan to relate our findings between GABAergic neurons and PNNs to hypothesize a connection between neural morphometry and connectivity and establish a relationship (or lack of relationship) between them.

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