Seasonal changes in the number of neurocytes containing lipofuscin pigment in selected areas of the brain of Rana temporaria L.

The number of neurocytes containing lipofuscin pigment (LEP) was determined in the nucleus infundibularis dorsalis (NID), the subfornical organ (SFO) and the medulla oblongata (MO) of the brain of sexually mature females and males of Rana temporaria L. approximately identical in length and age. The frogs were captured in their natural habitat in seven periods of the annual cycle. The number of LFP-positive neurocytes shows distinct seasonal variations in the analyzed areas. In general, neurocytes containing LFP were found in higher numbers during the winter months, and their significant drop was observed in summer. The results seem to suggest that cells containing LFP represent a certain kind of dynamic cellular system responding to various internal and/or external factors changing within a year.