European Journal of Anatomy

Official Journal of The Spanish Society of Anatomy
Cover Volume 4 - Number 3
Eur J Anat, 4 (3): 169-176 (2000)

Evolution of synaptic body numbers in the pineal gland of the cat over a 24-hour period in spring: A descriptive morphometric and statistical analysis

Martinez-Soriano F., Ruiz-Torner A., Lombillo de Onate M., Valverde-Navarro A.A.

Dpto. de Ciencias Morfologicas, Facultad de Medicina, Avda. Blasco Ibez 15, 46010 Valencia, Spain

ABSTRACT Eighteen cross-bred male cats (2650750 g) were kept for three weeks with environmental lighting and under the same feeding (ad libitum) and temperature conditions (18-22C). The animals were sacrificed in the spring in groups of three at 4 h intervals with the following GMT time sequence: 06:00, 10:00, 14:00, 18:00, 22:00, and 02:00 hours. During the circadian cycle, significant variations were observed in the number of synaptic ribbons and synaptic spherules in the pineal glands of the animals, with maximum and minimum values at 02:00 and 14:00 hours, and at 10:00 and 02:00 hours, respectively. Analysis of variance (ANOVA) showed these differences to be statistically significant (F-ratio: 43.513; p<0.0001 for synaptic ribbons, and F-ratio: 6.0; p<0.005 for synaptic spherules). The number of synaptic ribbons was found to be significantly higher (p<0.0001) at night (67.3%) than in the daytime (32.6%), while the number of synaptic spherules was 59.1% and 40.8% in the daytime and at night, respectively. The polynomial correlation between the evolution of the synaptic ribbons and the time point was very positive (R = 0.8). The circadian variations observed in the intermediate synaptic bodys (ISBS) population were not significant, either for triangular synaptic bodies (TSB) (p<0.07) or for rectangular synaptic bodies (RSB) (p<02). Finally, the total number of synaptic ribbons observed in the photophase merged to form "fields" of three or more elements. These fields were more commonly observed in pinealocyte prolongations than in areas close to the nucleus.

Keywords: animal experiment, animal tissue, article, cat, circadian rhythm, feeding, illumination, male, morphometrics, nonhuman, pineal body, statistical analysis, synapse, temperature

European Journal of anatomy
ISSN 2340-311X (Online)