Endomorphin-2 immunoreactivity in the cervical dorsal horn of the rat spinal cord at the electron microscopic level.
Neuroscience
; 113(3): 593-605, 2002.
Article
en En
| MEDLINE
| ID: mdl-12150779
Endomorphin-2 is a newly discovered endogenous opioid peptide with high affinity and selectivity for the micro-opioid receptor, and potent analgesic activity, particularly in the spinal cord. Using immunoelectron microscopy, we examined the ultrastructure of the endomorphin-2-like immunoreactive processes and their synaptic relationships in the spinal cord. Endomorphin-2-like immunopositive dense-cored vesicles were observed in many axon terminals, and, in a few cases, were observed together with immunonegative dense-cored vesicles. Immunopositive axons with or without myelination were also observed. The endomorphin-2-like immunoreactive axon terminals formed synapses with both immunopositive and immunonegative processes. Most synapses were asymmetrical, but symmetrical synapses were also found. Examples of axo-dendritic, axo-somatic and axo-axonic contacts were observed. This first demonstration of the ultrastructure and synaptic relationships of endomorphin-2-like immunoreactive axon terminals in the spinal cord dorsal horn provides morphological evidence that this peptide functions as a transmitter regulating pain processes.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oligopéptidos
/
Microscopía Inmunoelectrónica
/
Células del Asta Posterior
Límite:
Animals
Idioma:
En
Revista:
Neuroscience
Año:
2002
Tipo del documento:
Article
País de afiliación:
Japón
Pais de publicación:
Estados Unidos