Electron microscopy: tight junctions in synapses of the chick ciliary ganglion.

Examination of the synaptic membranes in calyciform endings of the chick ciliary ganglion has shown tight junctions selectively located on axon hillocks of postsynaptic neurons. Observations of similar membrane fusion in other junctions that involve electrotonic transmission suggest the possibility of identifying electrotonic junctions by electron microscopy.

The fine structure of synapses in the ciliary ganglion of the chick.

Ciliary ganglia of chick embryos and newly hatched chicks were examined in the light and electron microscopes. Particular attention was given to the fine structure of calyciform synapses, which are characteristically found in ciliary ganglia of birds. The calyciform endings are characterized by large expansions of the presynaptic axons upon ganglion cells, and the terminal processes extend over a considerable area of the cell surface.

Electron microscopic observations on the taste buds of the rabbit.

An examination of the fine structure of the taste buds in the rabbit was undertaken. Gustatory epithelium was fixed in OsO(4) or 1 per cent KMnO(4) solution, containing polyvinylpyrrolidone (PVP). Thick sections were examined in the phase microscope and contiguous sections prepared for the electron microscope.

Electron microscopic observations of the olfactory mucosa and olfactory nerve.

The olfactory receptor cell is characterized by a distal process (the dendrite) which terminates in the olfactory passage as the olfactory rod. The olfactory rod is provided with numerous cilia which are similar in structure to those seen in other tissues. The central processes of the bipolar cell constitute the fila olfactoria.