Ultrastructure of vesicourethral innervation. III. Axoaxonal synapses between postganglionic cholinergic axons and probably SIF-cell derived processes in the feline lissosphincter.
Ultrastructurally nonspecialized axoaxonal-type synapses between postganglionic cholinergic axons innervating the lissosphincter and apposed probably SIF-cell derived neuronal processes are described. These processes were considered as the peripheral extraganglionic counterparts of those belonging to type I SIF cell interneurons, described in many mammalian peripheral autonomic ganglia. On this basis, the herein reported cholinergic/probably SIF-cell derived axoaxonal-type synapses are proposed as an auxiliary mechanism of prejunctional catecholaminergic inhibition of the normally excitatory cholinergic (postganglionic parasympathetic) neuroeffector transmission in the feline lissosphincter.
Elbadawi
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D000818:Animals; D001338:Autonomic Fibers, Postganglionic / Q000648:ultrastructure*; D001369:Axons / Q000648:ultrastructure*; D002415:Cats; D002799:Cholinergic Fibers / Q000648:ultrastructure*; D007395:Interneurons / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D009451:Neuroeffector Junction / Q000648:ultrastructure; D013569:Synapses / Q000648:ultrastructure*; D009435:Synaptic Transmission; D014521:Urethra / Q000294:innervation*; D001743:Urinary Bladder / Q000294:innervation*