Ultrastructure of the pineal body of the common vampire bat, Desmodus rotundus

Abstract

The type AB pineal body of the common vampire bat, Desmodus rotundus, was recessed and lobulated, was extensively vascularized and intimately related to great veins, and was unassociated with the epithalamic region. The habenular and the posterior commissures coursed anteriorly and were unassociated with the pineal. The saccular suprapineal recess of the third ventricle extended dorsally juxtaposed to the pineal body. These anatomical features are likely to make pinealectomies in the vampire more difficult to manage. The pineal parenchyma consisted of light pinealocytes surrounded by canaliculi of various sizes, often transmitting unmyelinated nerve fibers and glial processes. Desmosomes were common. The pinealocyte nuclei were large and highly infolded; characteristic cytoplasmic constituents included abundant dilated Golgi complexes associated with clear vesicles, numerous polyribosomes, few single cisternae of ribosome-studded rough endoplasmic reticulum, mitochondria, and occasional multivesicular bodies and lysosomes. Almost all pinealocytes exhibited centrioles and some, in addition, displayed basal bodies but rarely ciliary shafts. A conspicuous feature of the pinealocyte cytoplasm was the presence of branched bundles of intermediate filaments, especially in the perinuclear zone. Siderotic macrophages, lipofuscin-pigment-containing phagocytic cells, mast cells, myelin bodies, and both fenestrated and continuous capillaries were present. The perivascular compartment was densely packed with unmyelinated nerve bundles containing small to large fibers exhibiting axoaxonic densities. Other constituents of the perivascular compartment were club-shaped pinealocyte processes filled with clear vesicles, microtubules, an occasional mitochondrion, glial processes, and collagen fibers. "Synapselike" contacts were observed between the axons and pinealocyte processes. Abundant pinocytotic vesicles in the capillary endothelium indicated active pinocytosis. Myelinated nerve fibers were lacking. The pineal ultrastructure of Desmodus is in part unlike that reported for other mammals, including bats.

Observations on the pineal gland of the big brown bat, Eptesicus fuscus: Possible correlation of melanin intensification with constant darkness

“…Even in mammalian pineals rudiments of photoreceptor elements such as synaptic ribbons, outer segments, cilia, and ciliary derivatives are Bhatnagar, 1988 This study Mprller, 1974Hiilsemann, 1971Theron et al, 1987LaEkoviC et al, 1992Quay, 1974Matsushima and Reiter, 1975Cozzi, 1986Santamarina, 1958Calvo et al, 1992 'M, melanin; L, lipofuchsin; H, hemosiderin. encountered (Pevet et al, 1977;Bhatnagar, 1988Bhatnagar, ,1992Bhatnagar, , 1994a. The presence Of rod-1ike phototransductory proteins in the adult Djungarian hamster pineal might represent remnants of a functional photoreceptor system which may also be active early in development (Foster et al, 1989).…”

Immunocytochemistry and calcium cytochemistry of the mammalian pineal organ: A comparison with retina and submammalian pineal organs

“…We found that the photoreceptor dendritic endings are of two main types: they bear rod-type (Fig. lc) or cone-type outer segments according to the presence of immunoreactive rhodopsin-, the corresponding S-antigen (or their absence, respectively), and vitamin A-binding sites Vigh, 1983, 1986a,b;1988, 1987, 1988, 1989, 1992Vigh-Teichmann, 1991).…”

“…2a) and pineal photoreceptors (Fig. 2b) fixed under dim red light (Vigh, 1987;Vigh-Teichmann, 1987, 1988;Vigh-Teichmann et al, 1987, 1988, 1989). The x 38,400. f: S-antigen-immunoreactive (black dots) process (p) of cat pinealocyte.…”

“…2a) and pineal photoreceptors ( Fig. 2b) fixed under dim red light (Vigh, 1987;Vigh-Teichmann, 1987, 1988;Vigh-Teichmann et al, 1987, 1988, 1989). The immunoreaction was decreased when the material was light-adapted prior to fixation (see the rod in Fig.…”

Fine structure of the pinealopetal innervation of the mammalian pineal gland

“…The majority of the fibers terminate with boutons located freely in the perivascular spaces or between the pinealocytes, without making synaptic junctional complexes with the pinealocytes. However, some synaptic junctions between the sympathetic terminals and pinealocytes have recently been demonstrated by electron microscopy (Bhatnagar, 1988;Huang and Lin, 1984). Although the number of such synaptic junctions is low, their functional role might be of importance for pineal physiology.…”