Some aspects of the sleep of lactating rat dams

• Autor(a) principal: Da Rocha, Lucia Regina Machado [UNESP]
• Data de Publicação: 2009
• Outros Autores: Hoshino, Katsumasa [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/227505
• topic: Lactation; Nursing rats; Sleep

Background and objective: The sleep of lactating rat dams were evaluated since informations on the subject are scanty. Methods: Electrographic recordings were made in nine rat dams, in different days after delivery (2nd to 20th day). Normal estrous cycling female rats, with previous motherhood experience, and four adult males were used as controls. Sleep-wakefulness was quantified and expressed as percentages of the total recording time and significance assessed by ANOVA, adopting significance level at the 0.05 level. Results: Total wakefulness was 43.4 ± 2.6% in control females, 44.3 ± 7.6% in the males and 55.1 ± 4.2% in LRD living with their 8 pups (difference rejected at the limit, p = 0.0547). The mean number of awakening episodes longer than 30 minutes was significantly greater in LRD. Synchronized wave sleep amounted to 46.6 ± 2.1%, 46.1 ± 7.6% and 41.9 ± 4.0%, respectively in control females, males and LRD. Desynchronized wave sleep (REM-sleep) was significantly reduced in LRD (3.0 ± 0.4%) compared to the values found in control females (10.0 ± 1.0%) and males (9.4 ± 0.6%). The average amounts of REM-sleep/hour along the recording period revealed to be constant and significantly lower in the lactating rat dams (3.0 ± 1.3%) comparatively to control females (11.6 ± 3.8%). An average of 1.2 ± 0.5 REM-sleep episodes/hour was also significantly lower in lactating females than in control females (3.2 ± 1.5). Conclusion: The results suggest an adaptive reorganization of the sleep architecture in the female rat during the nursing period.