1. Where is your rectal gland? Karen Hong Warren Pan Chela Brown Ashish Sharma Brittany Scarpato

2. Dogfish Shark (Squalus acanthias) rectal gland: a great model Purpose of the rectal gland A single cell type--highly specialized for transepithelial salt secretion Holds the World Record for: Na/K ATPase activity, Na/K/2Cl cotransporter activity (50x greater than mammalian kidney), and CFTR chloride channel activity One artery (usually), vein, duct--easy to cannulate and use for perfusion studies Model for hormonal regulation

4. K+K+ Na + BL SideApical Side Na + K+K+ 2 Cl - CFTR Cl- K+K+ -70mV TAL vs the shark rectal gland Absorption v. Secretion K+K+ Na + BL SideApical Side K+K+ Na + K+K+ 2 Cl - Cl- Barttin ClC-Kb

5. Rectal Gland Cell Model K+K+ Na + Basolateral Side Apical Side Na + K+K+ 2 Cl - CFTR Cl- K+K+ cAMP 5’AMP C ATP PDE K+

6. Rectal Gland Cell Model K+K+ Na + Basolateral Side Apical Side Na + K+K+ 2 Cl - CFTR Cl- K+K+ BaCl 2 + cAMP 5’AMP C ATP PDE IBMX Forskolin K+ Bumetanide Ouabain

7. Rectal Gland Cell Model K+K+ Na + Basolateral Side Apical Side Na + K+K+ 2 Cl - CFTR Cl- K+K+ K+ Cl- -70mv -15mv

8. Rectal Gland Cell Model K+K+ Na + Basolateral Side Apical Side Na + K+K+ 2 Cl - CFTR Cl- K+K+ K+ Cl- Approaching -15mv -15mv K+ BaCl 2 + K+

9. The Shark Rectal Gland: A Model Secretory Epithelium Hypothesis: Does inhibition of basolateral membrane proteins inhibit chloride secretion through apical CFTR?

10. In Vivo Dissection In Vitro Perfusion Methods

11. Artery Duct Vein Set-up

12. F + I Bumet F + I Ouabain F + I

14. Conclusions Bumetanide inhibits cotransporter Ouabain inhibits the ATPase enzyme, which in turn inhibits the cotransporter Barium chloride inhibits by depolarization

15. Future Suggested Experiments Administer bumetanide and barium chloride All three drugs Change the order the drugs are administered Vary the perfusion times for each drug Change the basal solution composition Increase extracellular potassium