抄録
Fluorescence- and electron-microscopic study was performed on nerve terminals close to cerebral blood vessels. For work with the electron microscope, subdural perfusion fixation with potassium permanganate was carried out. Some aminergic terminal boutons containing large and small cored vesicles were observed contiguous to blood vessels in the cerebral cortex of the rat deprived of the bilateral superior cervical ganglion. Since these terminals are found in the rat after bilateral superior cervical ganglion excision, they probably originate from central catecholaminergic neurons in the brain stem. In addition to aminergic terminal boutons, non-aminergic nerve terminals containing non-cored vesicles also ended in the capillaries. These findings suggest that central aminergic and non-aminergic neurons might play some role in cerebral blood flow regulation. On the other hand, two types of axon terminal, aminergic and non-aminergic, were observed in the adventitia of the basilar artery. Observation of separated sections would seem to indicate that sometimes two types of nerve fibers make contact with each other. During observation of serial sections, however, fusions of synaptic vesicles in the two types of nerve terminals were observed at membrane apposing muscle cells respectively. These facts suggest that two different types of axon terminals independently release “transmitters” toward muscle cells.
