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Nerve terminals and synapses in the cardiac ganglion of the adult lobster Homarus americanus
Author(s) -
Morganelli Peter M.,
Sherman R. G.
Publication year - 1987
Publication title -
journal of morphology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 74
eISSN - 1097-4687
pISSN - 0362-2525
DOI - 10.1002/jmor.1051910208
Subject(s) - homarus , biology , axon , synaptic vesicle , ganglion , synapse , ultrastructure , anatomy , free nerve ending , terminal nerve , vesicle , axon terminal , terminal (telecommunication) , neuroscience , zoology , telecommunications , biochemistry , genetics , crustacean , membrane , hormone , computer science
The cardiac ganglion in the lobster Homarus americanus was examined with a transmission electron microscope. Nerve terminals often existed in large aggregations surrounded by glial and connective tissue elements. Axo‐axonic and axo‐dendritic synapses were present. Six ultrastructurally different types of nerve terminal, each containing an abundance of vesicles, were distinguished: three formed discrete chemical synapses as indicated by typical release site morphology; three did not. The latter appear to be neurosecretory axon terminals of extrinsic neurons. More than one morphologically distinct type of synaptic vesicle occurred commonly in a given terminal, suggesting the presence of coexisting neurotransmitters and/or neuroregulatory factors. Symmetrical chemical synapses and electrotonic junctions between axons were present.