The Neurochemistry of GALP:
Where Form Meets Function
Rachna Goswami
Leo 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…
2
Plasma LH Levels (ng/ml)
***
1.5
1
0.5
0
Control
GALP
MALE
Control
GALP
FEMALE
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