Influence de la photopériode sur l'ultrastructure de l'épiphyse avant et pendant la phase génitale saisonniére chez la femelle du lérot (Eliomys quercinus)

Abstract

The pinealocyte of the female garden dormouse presents ultrastructural characteristics correlated with the sexual cycle. In winter, during the period of sexual quiescence, the pinealocyte is very rich in liposomes, myelinic bodies and lysosomes; the same holds during the summer quiescence state. These organelles and a great number of intracellular vacuoles are very well developed in dormice artificially maintained in anoestrous during the normal sexual activity period by light deprivation. In spring liposomes are strongly reduced in animals that are awake and sexually active, whereas the number of "synaptic ribbons" and of densecored vesicles increases. This ultrastructural aspect can be obtained during winter quiescence in animals living at 22 degrees C, under continuous light, and showing early sexual activation. If illumination is prolonged over the seasonal sexual phase dilated cisterns of granular endoplasmic reticulum, filled with proteinaceous material, appear in the cell. It seems that light no more activates, but inhibits gonadostimulator mechanisms. The pinealocyte's ultrastructural elements which are characteristic of a definite sexual state generally develop before this state is fully established. Actually, the functional significance of these organelles is not known.

Effect of castration and adrenalectomy on the ultrastructure of pinealocytes in the female garden dormouse (Eliomys quercinus L.) under different conditions of lighting and temperature during the normal period of hibernation

“…The two characteristic ultrastructural aspects of the pinealocytes previously described, i.e., the anoestrus-related aspect seen in hibernating animals (Richoux et aI., 1975) or in darkened animals during spring or summer (Roux et al, 1977) and the sexual activityrelated aspect observed in normal sexually active animals in spring (Roux et al, 1977) or in continuously illuminated animals during the winter , could again he demonstrated in the present material.…”

“…We demonstrated the typical ultrastructural aspects of this pineal endocrine cell, varying with the photoperiodicity and sexual activity (Roux et al, 1977(Roux et al, , 1979(Roux et al, , 1981.…”

The proteinaceous content and possible physiological significance of dense-cored vesicles in hamster and mouse pinealocytes

“…The presence of 5-HT in DCV varies in different species, depending upon the quantity of remaining 5-HT (which is not rapidly metabolized) and probably also, in a given species, upon daily changes ; the circadian rhythm of 5-HT and its related indoleamines is well known (Quay, 1974 ;Wurtman et al, 1968 ;Axelrod, 1974Axelrod and Zatz, 1977 (Roux et al, 1977) and after blinding and continuous darkness in hamsters (Sheridan, 1975) (Romijn, 1975), hamsters (Lin et al, 1975 ;Sheridan, 1975) and mice (Pellegrino de Iraidi, 1969) ; administration of parasympatholytic drugs in rabbits (Romijn, 1976) ; surgical castration in rats (Karasek et a/., 1976) ; injection of human chorionic gonadotropin (HCG) and pregnant mare serum gonadotropin (PMSG) in rats (Karasek and Marek, 1978) ; in the presence of norepinephrine (NE) or dibutyryl-cyclic-adenosine 3'-5'-monophosphate (db-c-AMP) in rat pineals cultured in vitro (Karasek, 1974) or in rabbits (Romijn and Gelsema, 1976). It has also been shown that a mean number of DCV in rabbits (Quay, 1974 ;Ebels, 1976 ;Benson et al, 1976 Finally, taking into account the detailed discussions of previous papers on reptiles, birds and mammals (Collin and Meiniel, 1971 ;Collin, , 1979Collin et al, 1977a, b ;Juillard and Collin, 1978) …”

Effets de l'énucléation oculaire bilatérale sur l'ultrastructure de l'épiphyse chez la femelle du Lérot (Eliomys quercinus L.). Corrélations avec l'axe hypothalamo-hypophyso-ovarien

“…All the animals stayed in permanent anoestrus even at long-term. The Kappers, 1969Kappers, , 1976Reiter, 1978 (Roux et Richoux et al, 1975 ;Roux et al, 1977Roux et al, , 1979 (Zweens, 1963), du taux d'hormone gonadotrope circulante (Zweens, 1965 ;Karasek et Marek, 1978) nous font penser, avec Pevet (1979) (Roux et al, 1977). Rappelons que tous ces animaux sont en état d'anaestrus.…”

“…Des vacuoles intracellulaires semblables ont été observées dans l'épiphyse de divers Mammifères (revue de Pevet, 1979). Pevet et Smith (1975) (Pevet, 1979 (Roux et al, 1977 ;Cordonnier et Roux, 1978). Ces organites sont rares chez les Lérots en état d'anoestrus : animaux hibernants, privés de lumière ou énucléés.…”