GABA- and glycine-immunoreactive terminals contacting motoneurons in lamprey spinal cord.
Double postembedding GABA- and glycine-immunostaining was performed on the lamprey (Lampetra fluviatilis) spinal cord after previous HRP labeling of motoneurons. Immunopositive boutons contacting motoneurons were counted and distinguished as GABA (39%), glycine (30%) and both GABA+glycine-immunopositive (31%). Densely-packed, flattened synaptic vesicles were only observed in glycine-immunopositive boutons while GABA-immunoreactive and GABA+glycine-immunoreactive boutons contained rounded or oval synaptic vesicles. Dense-core vesicles of different diameters were associated with conventional synaptic vesicles in 74% of GABA-only-immunopositive boutons, 50% of double GABA+glycine-immunopositive boutons, but were only observed in 9% of glycine-only-immunopositive boutons. The presence of terminals immunoreactive to either GABA or glycine contacting the motoneurons suggests that there is a morphological substrate for both GABAergic and glycinergic postsynaptic inhibition of motoneurons in the lamprey spinal cord.
Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia.
N P
NP
Vesselkin
J P
JP
Rio
V O
VO
Adanina
J
J
Repérant
D000465:Algorithms; D000818:Animals; D000918:Antibody Specificity; D001369:Axons / Q000502:physiology / Q000648:ultrastructure; D003712:Dendrites / Q000502:physiology / Q000648:ultrastructure; D005998:Glycine / Q000502:physiology*; D006735:Horseradish Peroxidase; D007150:Immunohistochemistry; D007798:Lampreys / Q000502:physiology*; D008854:Microscopy, Electron; D009046:Motor Neurons / Q000502:physiology* / Q000648:ultrastructure; D009411:Nerve Endings / Q000502:physiology* / Q000648:ultrastructure; D018377:Neurotransmitter Agents / Q000502:physiology*; D013116:Spinal Cord / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D018377:Neurotransmitter Agents; D005680:gamma-Aminobutyric Acid; D006735:Horseradish Peroxidase; D005998:Glycine