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Isometric force of isolated extraocular muscles of wild cowbirds
Author(s) -
Allawzi Ayed Mamdouh,
Grelle Eve Nicole,
Teclaw Mary Ellen,
Moore Bret,
FernándezJuricic Esteban,
Pelaez Nancy
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.801.15
Subject(s) - isometric exercise , extraocular muscles , anatomy , biology , stimulation , neuroscience , acetylcholine , reflex , depolarization , eye movement , biophysics , endocrinology , physiology
Recent studies show that the degree of eye movements varies substantially between different bird species. This variation is important from an evolutionary perspective, because species with a high degree of eye movement can change substantially the configuration of their visual fields, and consequently, visual coverage. More studies are necessary to understand the physiological basis of eye movements from a comparative perspective. Extraocular muscles of brown‐headed cowbirds (a species that shows a high degree of eye movement) were isolated and placed in a muscle bath, and isometric force was recorded in response to Acetylcholine (ACh) or KCl depolarization. With both treatments, stimulation caused a decline in muscle force, suggesting that the isolated muscle was pre‐contracted. Relaxation could be due to stimulation of inhibitory pre‐synaptic neurons. As a next step, experiments with cowbird extraocular muscle will be conducted in the presence of tubocurarine to induce relaxation so that experiments can be conducted to establish a normalized length‐tension curve for cowbird extraocular muscles.