The Harderian Gland Revealed: Regeneration and Recovery of Chemosensory Function

The Harderian Gland Revealed: Regeneration and Recovery of Chemosensory Function

Andy Fraser Dr. Robert Mason & Chris Friesen

Department of Zoology Oregon State University

Corvallis, ORQuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

• Salamanders, for example, are able to

regenerate limbs, tail, eyes, jaws, and heart.

• We are largely unable to regenerate crucial

organs and tissues.

• Cures for debilitating diseases and injuries.

• We know surprisingly little about how

regeneration works.

• It is crucial that we study new vertebrate

models.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

Summer feeding (~3 months)

Winter Dormancy (~ 8 months)

Mating (~ 4 weeks)

• Detection of chemical cues– Olfaction

• Volatile

– Vomerolfaction• Nonvolatile

– Harderian Gland (HG)• Solubizing agents • Binding proteins

Chemoreception

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

• Hypothesis:– The Harderian gland in

the red sided garter snake is able to regenerate and regain its function over time.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (Uncompressed) decompressor

are needed to see this picture.

POIOLD

x

x

x

Unilateral HDX

Bilateral HDX

Sham

YY

Y

N=28

N=28

N=28

Experimental Design

x

xx

Unilateral HDX

Bilateral HDX

Sham4 wks

N = 21

8 wks

N = 21

12 wks

N = 21

16 wks

N = 21

xx

x7

7

7

xxx

7

7

7

x

xx

7

7

7

x

xx

7

7

7

Experimental Design

Behavior Trials: Y-Maze

• Used to observe deficits in trailing behavior caused by removal of HG.

– In this case we know that garter snakes will trail worms.

Used coin flip to randomize which arm got

trail.

Y-Maze

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

t1 t2 t3 t4

Time Period

Proportion

ShamUniBi

N=7 N=7 N=7 N=7 N=7 N=7 N=7 N=7 N=7 N=7 N=7 N=5

Interpretation of Results

• Two Hypotheses

– 1. The HG regenerated more quickly than

expected

– 2. The IO portion of the HG hypertrophied or is

sufficient.

• Dr. Robert Mason

• Chris Friesen and Rocky Parker

• Dr. Kevin Ahern

• Howard Hughes Medical Institute

Acknowledgments