Immunoreactivity of synapses on primary afferent axons and sensory neurons in lamprey spinal cord (<Emphasis Type="Italic">Lampetra fluviatilis</Emphasis>)

The ultrastructure and immunospecificity of synapses on primary afferents and dorsal sensory cells (DCs) were studied in lamprey (Lampetra fluviatilis) spinal cords. Using the postembedding immunogold method with a combination of antibodies—polyclonal antibodies to glutamate and monoclonal antibodies to gamma-aminobutyric acid (GABA)—the presence of GABA-positive on the primary afferent axons and GABA-and glutamate-immunopositive synapses on the DC somatic membranes have been shown. Thus, it is obvious that sensory information in the lamprey is controlled by both presynaptic inhibition via synapses on the primary afferent axons and by direct synaptic influence on the body of the sensory neuron.