The Neurochemistry of GALP: Where Form Meets

Function

Rachna GoswamiLeo Reap

What is GALP?• Galanin-like peptide (GALP): neuropeptide; only

expressed in a small number of neurons within the hypothalamus  

• GALP expression is drastically reduced during fasting, anorexia, and diabetes.

• GALP acts to alter food intake and metabolic rate, and it also functions to stimulate reproductive physiology and behaviors. 

• The only two factors that regulate GALP are insulin and leptin.

Through our research last summer on pre-pubertal rats we discovered…

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Rich N, Reyes P, Reap L, Goswami R, Fraley GS 2007 Sex differences in the effect of prepubertal GALP infusion on growth, metabolism and LH secretion. Physiology and Behavior in press

Rich N, Reyes P, Reap L, Goswami R, Fraley GS 2007 Sex differences in the effect of prepubertal GALP infusion on growth, metabolism and LH secretion. Physiology and Behavior in press

Rich N, Reyes P, Reap L, Goswami R, Fraley GS 2007 Sex differences in the effect of prepubertal GALP infusion on growth, metabolism and LH secretion. Physiology and Behavior in press

Since GALP expression is the same in both males and females, these findings lead us to believe that the target sites for GALP neurons are sexually dimorphic.

What are the projections of GALP through the brain?

Neuronal Tract-Tracing

Phaseolus Vulgaris

Arcuate Nucleus

GALP Sexually Dimorphic?

Immunocytochemistry

• Stain brain sections with antibody solutions

• Assign each antibody a different color through the use of different fluorescent dyes

• Using fluorescence microscope, we will be able to tell which neural fibers transport GALP and to which areas of the brain they project

Summary

Currently, we have:

1) Stereotaxically injected Phaseolus Vulgaris into rat brains

2) Processed brains

3) Successfully done preliminary ICC

Acknowledgments

Dr. Fraley

HHMI

NIH (K01 DK066238-01A1)

REACH

Hope College