title: Electron microscopy of adrenergic, cholinergic, and "p-type" nerves in the myometrium and a special kind of synaptic contacts with smooth muscle cells.
abstract: In the cat uterus, three types of axons have been indentified by electron microscopy on the basis of the appearance of the synaptic vesicles in the axon varicosities following treatment with 5-hydroxydopamine: (1) most axons were adrenergic, with numerous small osmiophilic vesicles of a diameter of approximately 50 nm. together with large (100 to 150 nm. in diameter) granules, (2) some axons contained only empty small granules together with the large granules; these are probably cholinergic, and (3) a small number of the axon varicosities had only large-sized vesicles with a moderately electron-dense content. They are interpreted as a polypeptide type of nerves ("p-terminals"). Close appositions at a distance of 25 nm. were sometimes found between the varicosities. A specialized neuromuscular connection was found: the muscle cells at "the end" of muscle bundles extended small stout processes, containing numerous myofilaments, onto a small nerve bundle, the distance being 20 to 25 nm.
mesh_terms: D000320:Adrenergic Fibers / Q000648:ultrastructure; D000818:Animals; D001369:Axons / Q000648:ultrastructure; D002415:Cats; D002799:Cholinergic Fibers / Q000648:ultrastructure; D005260:Female; D006892:Hydroxydopamines; D009215:Myometrium / Q000294:innervation* / Q000648:ultrastructure; D009469:Neuromuscular Junction / Q000648:ultrastructure*; D013572:Synaptic Vesicles / Q000648:ultrastructure; D014599:Uterus / Q000294:innervation*
chemical_list: D006892:Hydroxydopamines