Disruption of circadian locomotor activity in rats after portacaval anastomosis is not gender dependent
✍ Scribed by Petra E. Steindl; Jeanne Gottstein; Andres T. Blei
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 652 KB
- Volume
- 22
- Category
- Article
- ISSN
- 0270-9139
No coin nor oath required. For personal study only.
✦ Synopsis
A recent study suggested that female rats are less affected by a portacaval anastomosis (PCA) than their male counterparts, as measured by body weight and changes in locomotor activity. In this study, we evaluated the entrainment of locomotor activity to the light! dark (LD) cycle, a consistent abnormality in the portacaval shunted rat. The degree of entrainment was measured in male and female rats before and after PCA or sham operation. All four groups of animals showed strong entrainment to an LD cycle before surgery. After portacaval anastomosis, male and female rats exhibited a highly significant decrease in overall motor activity as compared with the preoperative period and as compared with sham-operated animals of the same gender. The percentage of total activity during daytime was significantly increased after portacaval anastomosis. The reduction in parameters of entrainment indicates a disruption of circadian function in both portacavalshunted groups. Portal pressure measurements confirmed the patency of the shunts. Cortical brain glutamine levels were similarly increased in male and female shunted rats. The loss of body weight was slightly, but not significantly, more pronounced in male animals after shunt surgery. In conclusion, our results do not support a role for gender in the disruption of circadian function in rats after PCA (J~EPATOLQGY 1995;22 1763-1768.)
The construction of a portacaval anastomosis (PCA) in the rat results in a variety of behavioral alterations, such as decreased spontaneous nighttime activity' and startle reactivity,' but without changes in motor coordination tasks and learning or memory function.' Different methods have been used to assess motor activity in these animals, either using an activity-meter and measuring the animal's exploratory activity for a limited time,3,4 measuring swim e n d ~r a n c e , ~ or measuring Abbreviations: PCA, portacaval anastomosis; LD, lightldark; HE, hepatic From the Departments of Medicine, Lakeside Veterans Administration