title: Electron microscopic and pharmacologic evidence for a functional adrenergic innervation of the smooth musculature in the human fallopian tube.
abstract: Triple fixation for electron microscopy of the isthmic region of the human Fallopian tube distinguished adrenergic nerve terminals through their content of synaptic vesicles with a diameter of 50-60 nm. Non-vascular adrenergic nerves were found both outside and within smooth muscle bundles. Adrenergic varicosities, partly devoid of their Schwann cell ensheathing, frequently approached the smooth muscle cells within a distance of about 200 nm, and sometimes as close as 60-100 nm. These close contacts often occupied a considerable area of the naked varicosity. Electrical field stimulation of adrenergic nerves in the isthmic smooth muscle preparations in vitro induced an alpha-receptor mediated, frequency-dependent contractile response. The results show that the sympathetic nerves in the human Fallopian tube are able to exert a motor control of its smooth musculature, and may thus be involved in local functions essential for the normal fertilization process.
mesh_terms: D000320:Adrenergic Fibers / Q000648:ultrastructure*; D000328:Adult; D004558:Electric Stimulation; D005187:Fallopian Tubes / Q000294:innervation*; D005260:Female; D006801:Humans; D008854:Microscopy, Electron; D008875:Middle Aged; D009119:Muscle Contraction; D009130:Muscle, Smooth; D009469:Neuromuscular Junction / Q000648:ultrastructure; D012583:Schwann Cells / Q000648:ultrastructure; D013569:Synapses / Q000648:ultrastructure