Synaptic organisation of the pelvic ganglion in the guinea-pig.
A semi-quantitative electron-microscopic study of neuronal cell bodies, nerve profiles and synapses in the anterior pelvic ganglia of the guinea-pig has been carried out following in vivo labelling of adrenergic nerve endings with 5-hydroxydopamine. Ganglion cells of three main types have been distinguished: 1) the majority (about 70%) not containing granular vesicles, probably cholinergic elements; 2) those containing large granular vesicles of uniform size (80-110 nm), with granules of medium density and prominent halos; and 3) those containing vesicles of variable size (60-150 nm), with very dense eccentrically placed granular cores. Some non-neuronal 'granule-containing' cells were present, mainly near small blood vessels. Some 95% of the total axon profiles within the ganglia were cholinergic, the remaining 5% were adrenergic. However, 99% of synapses (i.e. axons within 50 nm of nerve cell membrane with pre- and post-synaptic specialisations) were cholinergic, and 1% were adrenergic. Only three examples of nerve cell bodies exhibiting both cholinergic and adrenergic synapses were observed. Unlike the para- and prevertebral ganglia, the pelvic ganglia contained large numbers of axo-somatic synapses. As many as 20% of the nucleated neuronal cell profiles displayed two distinct nuclei.
D000320:Adrenergic Fibers / Q000648:ultrastructure; D000818:Animals; D002415:Cats / Q000033:anatomy & histology; D002799:Cholinergic Fibers / Q000648:ultrastructure; D005725:Ganglia, Autonomic / Q000648:ultrastructure*; D006168:Guinea Pigs / Q000033:anatomy & histology*; D008297:Male; D008854:Microscopy, Electron; D009416:Nerve Regeneration; D009474:Neurons / Q000502:physiology / Q000648:ultrastructure; D010388:Pelvis / Q000294:innervation*; D051381:Rats / Q000033:anatomy & histology; D013569:Synapses / Q000648:ultrastructure*