Effects of maternal care and social interactions on the function of the circadian glucocorticoid rhythm

During the development of an organism, early life environment, such as features of maternal care and social interactions, is very important for the proper development of the Hypothalamic Pituitary-Adrenal (HPA) Axis, a system that regulates stress responsiveness. In this project we are using an animal model of early life stress and are intended to show that how the social interactions (housing group and isolation) during the late pre-weaning and early post-weaning periods affect the animal’s glucocorticoid circadian rhythm, and how the maternal care affect the development of endocrine and behavioral responses to stress. Our study focus on Corticotropin Releasing Hormone Stress System, Serotonin Brain System and Growth Hormone Axis.

Insitu hybridization
Protein identification by ELISA
Radioimmunoassay for circadian corticosterone/ACTH
Animal procedures
Student Tasks: All animal works were finished. Student who is involved in this project will help with:
Brain sectioning
Insitu hybridization
Cell culture ( transformation, Mini-prep and Midi- prep ) to make plasmid DNA
Image capturing and quantification.
Analyzing previously collected data by using Excel and Statview.

Student will be working with technicians to accomplish these tasks.

Minimum Qualifications: General biology courses, general chemistry courses and computer skills (Excel, Word, EndNote and Statview). Willingness to work at least 6-8 hrs per week in 3-4hr blocks.

Stress Response and Growth: Impact of Early Life Stress
The focus of this project is to understand the role of critical developmental periods which, when altered, lead to growth failure using the rat as an animal model. Efforts are concentrated on two stages of the rat's development, i.e., the first two weeks of life, when activation and termination of stress can be altered in opposite directions, depending on the timing of stressors and on the post-weaning period when the rat is no longer dependent upon maternal care for survival. Our laboratory collaborates with Juan F. Lopez and Seymour Levine as we study the hypothalamus, hippocampus, and pituitary. These structures are thought to exert important neural and endocrine control upon the LHPA and the growth hormone (GH) axes. It is proposed to: 1) examine the consequences of early stress (maternal deprivation at specified times in life) or pharmacological agents (glucocorticoids) on growth parameters; 2) examine if the individual differences in stress responsiveness resulting from maternal deprivation or glucocorticoid treatment alter the expression of molecules linked to a functional GH axis during development; and 3) attempt to revert the long-term negative effects of maternal deprivation by blocking the LHPA response to stress during early life with a CRH antagonist. This project also explores psychopathology in families of children evaluated for short stature in a Pediatric Endocrine clinic. Most recently we have expanded this project with Audrey Seasholtz as we look into molecular mechanisms responsible for growth and HPA alterations. We also have initiated a new line of work that focuses in the Brain Serotonin System with Paresh Patel and Charles Neal. This project is supported by NICHHD branch of NIH.

Please go to UROP website for more details


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