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Structure and function of the velar muscle in the New Zealand hagfish Eptatretus cirrhatus : response to temperature change and hypoxia
Author(s) -
Coxon S. E.,
Davison W.
Publication year - 2011
Publication title -
journal of fish biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.672
H-Index - 115
eISSN - 1095-8649
pISSN - 0022-1112
DOI - 10.1111/j.1095-8649.2011.03028.x
Subject(s) - hagfish , biology , hypoxia (environmental) , oxygen , anatomy , biochemistry , vertebrate , chemistry , gene , organic chemistry
The rate of velar movement in Eptatretus cirrhatus , as determined by electromyography, increased with Q 10 3·2 during exposure to temperatures between 7 and 19° C and increased 3·9 fold during exposure to hypoxia (oxygen partial pressure = 6·67 kPa). This confirms the role of the velum in generating respiratory currents and modification of its activity in response to changes in metabolic demand or environmental oxygen availability. The maximum velar rate observed was 168 beats min −1 , higher than that recorded in any hagfish species to date. Fibres of musculus craniovelaris were exclusively small, red (slow‐twitch) fibres, consistent with a high aerobic capacity required by fibres involved in rhythmic, ongoing activity.