Ultrastructural localization of ?-Arrestin-1 and -2 in rat lumbar spinal cord

✍ Scribed by Kittel, Agnes; Komori, Naoka

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 481 KB
• Volume: 412
• Category: Article
• ISSN: 0021-9967
• DOI: 10.1002/(sici)1096-9861(19991004)412:4<649::aid-cne6>3.0.co;2-4

✦ Synopsis

␤-arrestins play significant roles in agonist-mediated desensitization of G proteincoupled receptors. Although the presence of ␤-arrestin subtypes, ␤-arrestin-1 and -2, in rat brain has been studied extensively, their existence in the spinal cord has not been described. In the current study, we performed immunohistochemical analyses of ␤-arrestins at both light and electron microscopic levels using rat lumbar 1-2 spinal cord segments. Intense immunoreactivity for ␤-arrestin-1 was found in the motoneurons in lamina IX of the ventral horn and elongated cells in the dorsal nucleus of Clarke. Modest immunoreactivity was detected among the neurons of laminae V and VII/VIII, and weaker immunoreactivity in laminae III, IV, and X. ␤-arrestin-2 immunoreactivity was also distributed through laminae III-X in the order of IX Ͼ dorsal nucleus of Clarke Ͼ V Ͼ VII/VIII Ͼ IV Ͼ III Ͼ X. Laminae I and II did not show immunoreactivity. At the electron microscopic level, both ␤-arrestin-immunoreactive and nonimmunoreactive dendrites were observed, whereas axons and terminal boutons were devoid of immunoreactivity. In immunoreactive dendrites most ␤-arrestin immunoreactivity was distributed throughout the cytoplasm, demonstrating their association with microtubules. In addition, strong immunoreactivity was often found at postsynaptic densities. Our results thus suggest ␤-arrestins' possible involvement in both motor and sensory mechanisms at the postsynaptic level in rat lumbar spinal cord.