3.1. Filament morphology
Filament morphology of channel catfish gills is
Type I according to the classification scheme of
Bijtel (1949). The filaments are free (not connected
with a septum) and alternate (proximal/
distal: right/left) as you move up or down the
arch. Adductor muscles are between the hemibranchs
and abductor muscles are located laterally
at the base of the filament where it attaches to
the arch. There was nothing unusual about the
morphology of channel catfish filaments or gills,
they are representative of many typical teleosts.
3.2. Efferent discharge characteristics
Visual inspection of the ventilation and nerve
recording traces did not reveal any obvious differences
between the anesthetized and decerebrate
preparations. Breath-to-breath interval was not
statistically different between anesthetized and decerebrate
fish either before or after paralysis.
Given that there was no effect of MS-222 anesthetic
on ventilation, data from the two experimental
preparations were combined