MELANIN IN THE PINEAL GLANDS OF CANIDAE

Abstract

Objective - to study the presence of melanin in the pineal gland (PG) and to assess the frequency of the pigmented glands occurrence in Canidae of different age groups. Material and methods. The objects of the research were raccoon dog (Nyctereutes procyonoides Grey), fox (Vulpes vulpes L.) and Arctic fox (V. lagopus L.). In immature (6-8 months) and adult (1,5-3,5 years) females of each species, the presence of the PG pigmentation was visually assessed and the proportion (%) of the pigmented and non-pigmented PG was calculated. The number of immature and adult animals was as follows: raccoon dog - n=4, n=15, fox - n=15, n=28, Arctic fox - n=14, n=14, accordingly. PG morphology was studied by histological methods; the sections were stained with hematoxylin and eosin and according to Masson-Fontana technique. Results. Clusters of melanin in the PG of studied species were located both on the periphery of the gland and near the blood vessels. The great variability of the PG pigmentation was detected. The age and the species membership affected the frequency of pigmented PGs findings. In raccoon dogs pigmented PGs were observed in immature individuals only (25 %), in foxes - in adults only (21,4 %). In blue foxes pigmented PGs were characteristic of both age groups, but with age their proportions decreased (from 21,4 to 7,1 %). Conclusions. A great variability in the degree of PG pigmentation was demonstrated. The frequency of the pigmented glands occurrence in Canidae is species-specific and depends on the age of the animals.

Keywords

pineal gland / Canidae / melanin / melatonin

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RIGHTS & PERMISSIONS

Kalinina S.N., Ilyukha V.A., Uzenbaeva L.B., Antonova Y.P., Bruler Y.S., Okulova I.I.