[MARMAM] New publication from Tift et al. for MARMAM community

Michael Tift mtift at ucsd.edu
Tue Jan 30 18:59:49 PST 2018

​​We are pleased to announce the publication of the following paper in the
current issue of Journal of Experimental Biology:

Tift MS, Huckstadt LA, Ponganis PJ. 2018. Anterior vena caval oxygen
profiles in a deep-diving California sea lion: arteriovenous shunts, a
central venous oxygen store and oxygenation during lung collapse. *Journal
of Experimental Biology* 221: jeb163428

URL: *http://jeb.biologists.org/content/221/1/jeb163428


Deep-diving California sea lions (*Zalophus californianus*) can maintain
arterial hemoglobin saturation (*S*O2) above 90% despite lung collapse
(lack of gas exchange) and extremely low posterior vena caval *S*O2 in the
middle of the dive. We investigated anterior vena caval *P*O2 and *S*O2 during
dives of an adult female sea lion to investigate two hypotheses: (1)
posterior vena caval *S*O2 is not representative of the entire venous
oxygen store and (2) a well-oxygenated (arterialized) central venous oxygen
reservoir might account for maintenance of arterial *S*O2 during lung
collapse. During deep dives, initial anterior vena caval *S*O2 was elevated
at 83.6±8.4% (*n*=102), presumably owing to arteriovenous shunting. It
remained high until the bottom phase of the dive and then decreased during
ascent, whereas previously determined posterior vena caval *S*O2 declined
during descent and then often increased during ascent. These divergent
patterns confirmed that posterior vena caval *S*O2 was not representative
of the entire venous oxygen store. Prior to and early during descent of
deep dives, the high *S*O2 values of both the anterior and posterior venae
cavae may enhance arterialization of a central venous oxygen store.
However, anterior vena caval *S*O2 values at depths beyond lung collapse
reached levels as low as 40%, making it unlikely that even a completely
arterialized central venous oxygen store could account for maintenance of
high arterial *S*O2. These findings suggest that maintenance of high
arterial *S*O2 during deep dives is due to persistence of some gas exchange
at depths beyond presumed lung collapse.

Please email me (mtift at ucsd.edu) if you would like a PDF copy of the paper.

Best regards,
*Michael S. Tift, PhD |**mtift at ucsd.edu <mtift at ucsd.edu>*
Postdoctoral Fellow
UC San Diego School of Medicine
Division of Physiology
University of California San Diego
*9500 Gilman Drive
Medical Teaching Facility*
*Mail Code 0623A*
La Jolla, CA 92093-0623 USA
Phone: 858 534 4190 <(858)%20534-4190>
Website <http://michaeltift.weebly.com/>
ResearchGate Profile <https://www.researchgate.net/profile/Michael_Tift>
Google Scholar Profile
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