Predominant presence of beta-arrestin-1 in small sensory neurons of rat dorsal root ganglia.

Reverse transcription-polymerase chain reaction and western immunoblot analyses were performed to demonstrate the presence of beta-arrestin-1 in rat dorsal root ganglion. beta-Arrestin-1 existed as two alternatively spliced variants, although predominantly in its untruncated form. Several factors affected the visualization of the truncated version on a sodium dodecyl sulfate-polyacrylamide gel; however, the isoform was clearly detected on a two-dimensional gel. We further localized beta-arrestin-1 immunoreactivity in the sensory neurons of the 5th lumbar dorsal root ganglia. Beta-arrestin-1-immunoreactive neurons accounted for approximately 60% of the sensory neurons, and approximately 88% of the beta-Arrestin-1 immunoreactive neurons fell into a category of small neurons having a diameter of 10-30 microm. Members of the arrestin superfamily play crucial roles in the desensitization of G protein-coupled receptors. Our data demonstrating the presence of beta-arrestin-1 in the rat dorsal root ganglion at both messenger RNA and protein levels support the idea that beta-arrestin- participates in receptor desensitization in the sensory neurons. Furthermore, because small-size neurons of dorsal root ganglion are often implicated in nociception, the predominant presence of beta-arrestin-1 immunoreactivity in small-size sensory neurons suggests that beta-arrestin-1 may have a role modulating nociceptive signals.