The Harderian Gland Revealed: Regeneration and Recovery of Chemosensory Function Andy Fraser Dr. Robert Mason & Chris Friesen Department of Zoology Oregon State University Corvallis, OR

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.

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

Hypothesis: –The Harderian gland in the red sided garter snake is able to regenerate and regain its function over time.

PO IO LD

x x x Unilateral HDX Bilateral HDX Sham Y Y Y N=28 Experimental Design

x x x Unilateral HDX Bilateral HDX Sham 4 wks N = 21 8 wks N = wks N = wks N = 21 x x x x x x x x x x x x 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.

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