Posters
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 preventing 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. However, it is also imperative to study the role GABA transmission relates with drug addiction and substance disorders including alcohol misuse. GABAergic neurons can be identified and quantified using antibodies that target GAD65 and GAD67. GAD65 is mostly abundant in axon terminals and is linked to synaptic vesicles while GAD67 is found throughout the cytoplasm, with a greater concentration in cell bodies. The purpose of this study is to quantify and analyze the expression of GAD65 and GAD67 in the brain of the Monodelphis Domestica.
Methods: A female Monodelphis Domestica was transcardially perfused with 4% paraformaldehyde and sliced at a thickness of 35 μm. Two antibodies for Glutamic acid decarboxylase (GAD65 and GAD67) were used to identify GABAergic neurons, following the ABC-DAB method of immunohistochemistry. The criteria for identifying GAD-positive neurons include presence of a dark brown reaction within the perikaryal cytoplasm. Using Image J software and stereological methods, midbrain sections were used to compare the number of cells between different sections.
Results: GAD67 and GAD65 are both used to identify GABAergic neurons. GAD65 neurons resembled a network of axon fibers, in contrast to GAD67neurons, which had a more clearly defined cell body and nucleus. Based on preliminary quantification of GAD67, there were 161 neurons in the dorsomedial periaqueductal gray nucleus (DMPAG) and 200 neurons in the dorsal tuberomammillary (DTM) nucleus. In the DTM region, there were 1.37 neurons per 2500μm2, while in the DMPAG region there were 0.73 neurons per 2500μm2. The expression of GAD67 neurons in the DMPAG were more dispersed but were larger in comparison to the neurons in the DTM. The mean intensities for GAD65 and GAD67 differed significantly in the SNR/SNCD area. GAD67 neurons showed a generally higher intensity than GAD65 neurons.
Conclusion: Our findings support the relevant literature regarding the way by which GAD67 and GAD65 are expressed. By assessing the expression of GABA neurons in various regions of the brain, our recent findings will contribute to the use of the Monodelphis as a model for neurological illnesses. Present-day epilepsy models including genetically epilepsy prone rats showed greater numbers of small, GABAergic neurons in comparison to Sprague-Dawley rats in the central nucleus of the inferior colliculus suggesting a deficiency in GABAergic transmission. We are currently assessing GABAergic neurons, using stereological methods, in the midbrain of the Monodelphis in response to an external stimulation, such as a visual or social stimulus. We plan to relate these findings to the pathophysiology of Epilepsy, Parkinson’s Disease, Schizophrenia, drug addiction, substance use disorder, and emotional disturbances.
Academic/Professional Position
Community Partner
Academic/Professional Position (Other)
Biomedical Sciences
Recommended Citation
Luna, Jatziry; Le, Truc; Zacarias, Esperanza I.; and Gil, Mario, "GABA Expression in the Monodelphis Domestica and Relevance to Neuropsychiatric and Neurological Disorders" (2024). Research Symposium. 63.
https://scholarworks.utrgv.edu/somrs/2023/posters/63
Included in
GABA Expression in the Monodelphis Domestica and Relevance to Neuropsychiatric and Neurological Disorders
Background/Purpose: Gamma-aminobutyric acid (GABA) is an amino acid that serves as the central nervous system's (CNS) main inhibitory neurotransmitter. By preventing 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. However, it is also imperative to study the role GABA transmission relates with drug addiction and substance disorders including alcohol misuse. GABAergic neurons can be identified and quantified using antibodies that target GAD65 and GAD67. GAD65 is mostly abundant in axon terminals and is linked to synaptic vesicles while GAD67 is found throughout the cytoplasm, with a greater concentration in cell bodies. The purpose of this study is to quantify and analyze the expression of GAD65 and GAD67 in the brain of the Monodelphis Domestica.
Methods: A female Monodelphis Domestica was transcardially perfused with 4% paraformaldehyde and sliced at a thickness of 35 μm. Two antibodies for Glutamic acid decarboxylase (GAD65 and GAD67) were used to identify GABAergic neurons, following the ABC-DAB method of immunohistochemistry. The criteria for identifying GAD-positive neurons include presence of a dark brown reaction within the perikaryal cytoplasm. Using Image J software and stereological methods, midbrain sections were used to compare the number of cells between different sections.
Results: GAD67 and GAD65 are both used to identify GABAergic neurons. GAD65 neurons resembled a network of axon fibers, in contrast to GAD67neurons, which had a more clearly defined cell body and nucleus. Based on preliminary quantification of GAD67, there were 161 neurons in the dorsomedial periaqueductal gray nucleus (DMPAG) and 200 neurons in the dorsal tuberomammillary (DTM) nucleus. In the DTM region, there were 1.37 neurons per 2500μm2, while in the DMPAG region there were 0.73 neurons per 2500μm2. The expression of GAD67 neurons in the DMPAG were more dispersed but were larger in comparison to the neurons in the DTM. The mean intensities for GAD65 and GAD67 differed significantly in the SNR/SNCD area. GAD67 neurons showed a generally higher intensity than GAD65 neurons.
Conclusion: Our findings support the relevant literature regarding the way by which GAD67 and GAD65 are expressed. By assessing the expression of GABA neurons in various regions of the brain, our recent findings will contribute to the use of the Monodelphis as a model for neurological illnesses. Present-day epilepsy models including genetically epilepsy prone rats showed greater numbers of small, GABAergic neurons in comparison to Sprague-Dawley rats in the central nucleus of the inferior colliculus suggesting a deficiency in GABAergic transmission. We are currently assessing GABAergic neurons, using stereological methods, in the midbrain of the Monodelphis in response to an external stimulation, such as a visual or social stimulus. We plan to relate these findings to the pathophysiology of Epilepsy, Parkinson’s Disease, Schizophrenia, drug addiction, substance use disorder, and emotional disturbances.