ABSTRACT
Data about the nervous regulation of secretion in nucleus sacci vasculosi of Scylliorhinus canicula are provided in the present study. The existence of cholinergic synapsis over secretory processes and electric synapsis among amyelinic fibers is shown. Likewise, images that demonstrate the existence of a type of merocrine secretion in which the secretory granules coming from the nucleus sacci vasculosi are emptied into the vessels, conserving their completeness while they pass through the pericapillary basal membrane are provided.
Subject(s)
Cerebral Ventricles/anatomy & histology , Fishes/anatomy & histology , Neurosecretory Systems/anatomy & histology , Secretory Rate , Animals , Capillaries/innervation , Capillary Permeability , Cytoplasmic Granules/ultrastructure , Synapses/ultrastructure , Synaptic Vesicles/ultrastructureABSTRACT
Adult hamsters were used for this electron microscopic study of the hypothalamic region. Specialized contacts between astrocytes and astrocytes, and between astrocytes and other cellular elements, are described and illustrated. The specialized inter-astrocytic junctions occur primarily in perivascular and subpial regions, but also in areas of high synaptic density. The junctions between astrocytic processes are of hemidesmosomal type. Astrocytes are connected to oligodendroglial cells by means of desmosomes, and to neuronal processes by means of zonulae occludens. The functional significance of these arrangements is discussed.