Inhibitory amino acid transmitters associated with axons in presynaptic apposition to cutaneous primary afferent axons in the cat spinal cord.
J Comp Neurol
; 452(2): 154-62, 2002 Oct 14.
Article
en En
| MEDLINE
| ID: mdl-12271489
The purpose of the present study was to characterize the transmitter content of structures in presynaptic apposition to the central terminals of cutaneous afferent fibers in the dorsal horn of the spinal cord. Axons in the Aalphabeta conduction velocity range were identified in adult cats, stained intra-axonally with horseradish peroxidase, and prepared for combined light and electron microscopy. In total, we labeled two slowly adapting (Type 1) axons, two hair-follicle afferents, and one rapidly adapting (Krause) afferent. Ninety-nine labeled boutons were examined through complete series of serial sections. Approximately 80% of boutons originating from rapidly adapting and hair-follicle afferents were postsynaptic to other axons, but only 50% of boutons from slowly adapting axons were associated with this type of arrangement. Postembedding immunogold reactions revealed that between 80% (for slowly adapting axons) and 100% (for rapidly adapting axons) of boutons presynaptic to primary afferents were immunoreactive for gamma-aminobutyric acid (GABA). The vast majority of these terminals (in excess of 80%) were also enriched with glycine. Therefore, presynaptic inhibition of these three functional classes of Aalphabeta cutaneous primary afferents is mediated principally by the subgroup of GABAergic interneuron that also contains glycine.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Terminales Presinápticos
/
Ácido gamma-Aminobutírico
/
Glicina
/
Inhibición Neural
/
Neuronas Aferentes
Tipo de estudio:
Risk_factors_studies
Límite:
Animals
Idioma:
En
Revista:
J Comp Neurol
Año:
2002
Tipo del documento:
Article
País de afiliación:
Reino Unido
Pais de publicación:
Estados Unidos