Table 2.

Mean (±s.d.) citrate synthase (CS) activity [μmol of substrate converted to product min–1 (international units) g–1 wet mass of tissue] at 20°C in opah extraocular muscles

NExtraocular muscleCitrate synthase activity (units g–1)
6Lateral rectus, proximal portion36.13±18.6
7Lateral rectus, distal portion3.65±1.62
9Superior rectus6.54±2.05
9Inferior rectus5.42±3.20
10Medial rectus13.13±3.85
2Medial rectus, proximal portion12.46
8Superior oblique7.33±5.34
8Inferior oblique3.22±1.40
  • CS activity is significantly higher in the proximal portion of the lateral rectus muscle (LRM) than in the distal portion of the LRM, the superior rectus, inferior rectus, superior oblique and inferior oblique muscles (ANOVA, P<0.05). In addition, the medial rectus muscle has a significantly higher CS activity than the inferior oblique muscle (ANOVA, P<0.05)