PVN-lesioned obese rats maintain ambulatory activity and its circadian rhythm.
We investigated physical activity and its circadian rhythm as well as food and water intake in PVN-lesioned rats compared to those of VMH-lesioned rats. Body weight, food and water intake and ambulatory activity were recorded automatically on a microcomputer on the fourth day after creation of the PVN or VMH lesion. The weight gain in the PVN-lesioned rats was almost the same as that of the VMH-lesioned rats. The PVN-lesioned rats maintained the same circadian rhythm of eating and drinking as the controls. The ambulatory activity in the VMH-lesioned rats during the 24-h period was significantly less than the sham-operated rats, but that of the PVN-lesioned rats was almost the same as the sham-operated rats. The dominance of ambulatory activity in the dark period was observed in the PVN-lesioned rats as well as controls, in contrast to the VMH-lesioned rats, in which circadian rhythm was abolished. These results demonstrate that the PVN-lesioned obese rats show clear differences in physiological behavior from the VMH-lesioned rats.
Tokunaga
K
K
Second Department of Internal Medicine, Osaka University Medical School, Japan.
Matsuzawa
Y
Y
Fujioka
S
S
Kobatake
T
T
Keno
Y
Y
Odaka
H
H
Matsuo
T
T
Tarui
S
S
D000818:Animals; D001835:Body Weight / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D005260:Female; D009043:Motor Activity / Q000502:physiology*; D009765:Obesity / Q000523:psychology*; D010286:Paraventricular Hypothalamic Nucleus / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D014630:Vagus Nerve / Q000502:physiology; D014697:Ventromedial Hypothalamic Nucleus / Q000502:physiology