2. THE NEUROHYPOPHYSIS
159
contents have been described in Carassius auratus, Gadus morrhua, and
Zoarces viviparus (,Palay, 1960; Lederis, 1962; Oztan, 1966). Scharrer
( 1962), working with Opsanus tau, has reported that similar large vesicles
may have openings which expose their finely granular contents to the
outer cytoplasm, but this may be an artifact of fixation. In addition,
Scharrer has reported the presence of cilia in the neurosecretory cells
of this species. The Golgi complex is found in the central zone, and it is
well developed; it has been described as consisting of narrow tubules and
vesicles, or as groups of agranular membranes, in Gadus morrhua, Cottzrs
bubalis, Salmo irideus, and Perca fluviatilis (Lederis, 1962; Follenius,
1963). There is almost universal agreement that the Golgi complex produces the elementary vesicles ( = elementary granules) which are the
neurosecretory material, as seen under the electron microscope ( Follenius,
1982,1963; Palay, 1960; Scharrer, 1962; Lederis, 1962).
The elementary vesicles, which can occur throughout the central
zone of the cytoplasm, have a complex structure. The outer surface is
smooth and consists of a single membrane, and immediately within it is a
narrow, clear zone. The center of the vesicle is full of a fine, osmiophylic,
electron-dense, and perhaps lipid-containing granular material ( Carassius
auratus, Palay, 1960; Mugil cephulus, Leray and Stahl, 1961; Gadus morrhua, Cottus bubalis, Salmo irideus, Perca fluviatilis, Follenius, 1963).
These elementary vesicles, which are seen in the cytoplasm of the
preoptic cells, are larger than the closely similar structures found in the
neighboring nucleus lateralis tuberis ( Salmo irideus, Perca fluviatilis;
Follenius, 1962, 1963). Although their size may vary between different
species, it is often possible to divide the elementary vesicles of a particular
species into two distinct ranges. If these correspond to the similar vesicles
present in the pars nervosa, as would seem reasonable, studies in Gadus
morrhua would suggest that arginine vasotocin is associated with those of
smaller size (Carassius auratus, Palay, 1960; Gadus morrhua, Lederis,
1962; Anguilla anguillu, Leatherland and Dodd, 1967). Leatherland and
Dodd (1967) have made the important observation that the two different
sizes of elementary vesicles present in the eel, AnguiUa anguillu, can be
correlated with two digerent types of preoptic cell. The larger elementary
vesicles, 2150 k 30 A in diameter, are associated with a more electrondense type of cell, which contains swollen and irregular cysternae in its
cytoplasm. In contrast, the smaller elementary vesicles, 1627 -C 31 A
across, are found in more electron-lucent preoptic cells, which possess a
narrow and regular endoplasmic reticulum. These results lead to the interesting speculation that the two neurohypophysial hormones of the teleost
fish may well be made by different cells within the preoptic nucleus.
Studies with the classic staining techniques suggest that neurosecre-
159
contents have been described in Carassius auratus, Gadus morrhua, and
Zoarces viviparus (,Palay, 1960; Lederis, 1962; Oztan, 1966). Scharrer
( 1962), working with Opsanus tau, has reported that similar large vesicles
may have openings which expose their finely granular contents to the
outer cytoplasm, but this may be an artifact of fixation. In addition,
Scharrer has reported the presence of cilia in the neurosecretory cells
of this species. The Golgi complex is found in the central zone, and it is
well developed; it has been described as consisting of narrow tubules and
vesicles, or as groups of agranular membranes, in Gadus morrhua, Cottzrs
bubalis, Salmo irideus, and Perca fluviatilis (Lederis, 1962; Follenius,
1963). There is almost universal agreement that the Golgi complex produces the elementary vesicles ( = elementary granules) which are the
neurosecretory material, as seen under the electron microscope ( Follenius,
1982,1963; Palay, 1960; Scharrer, 1962; Lederis, 1962).
The elementary vesicles, which can occur throughout the central
zone of the cytoplasm, have a complex structure. The outer surface is
smooth and consists of a single membrane, and immediately within it is a
narrow, clear zone. The center of the vesicle is full of a fine, osmiophylic,
electron-dense, and perhaps lipid-containing granular material ( Carassius
auratus, Palay, 1960; Mugil cephulus, Leray and Stahl, 1961; Gadus morrhua, Cottus bubalis, Salmo irideus, Perca fluviatilis, Follenius, 1963).
These elementary vesicles, which are seen in the cytoplasm of the
preoptic cells, are larger than the closely similar structures found in the
neighboring nucleus lateralis tuberis ( Salmo irideus, Perca fluviatilis;
Follenius, 1962, 1963). Although their size may vary between different
species, it is often possible to divide the elementary vesicles of a particular
species into two distinct ranges. If these correspond to the similar vesicles
present in the pars nervosa, as would seem reasonable, studies in Gadus
morrhua would suggest that arginine vasotocin is associated with those of
smaller size (Carassius auratus, Palay, 1960; Gadus morrhua, Lederis,
1962; Anguilla anguillu, Leatherland and Dodd, 1967). Leatherland and
Dodd (1967) have made the important observation that the two different
sizes of elementary vesicles present in the eel, AnguiUa anguillu, can be
correlated with two digerent types of preoptic cell. The larger elementary
vesicles, 2150 k 30 A in diameter, are associated with a more electrondense type of cell, which contains swollen and irregular cysternae in its
cytoplasm. In contrast, the smaller elementary vesicles, 1627 -C 31 A
across, are found in more electron-lucent preoptic cells, which possess a
narrow and regular endoplasmic reticulum. These results lead to the interesting speculation that the two neurohypophysial hormones of the teleost
fish may well be made by different cells within the preoptic nucleus.
Studies with the classic staining techniques suggest that neurosecre-