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

Reverse transcription-polymerase chain reaction and western immunoblot anal yses were performed to demonstrate the presence of beta-arrestin-1 in rat d orsal root ganglion. beta-Arrestin-1 existed as two alternatively spliced v ariants, although predominantly in its untruncated form. Several factors af fected the visualization of the truncated version on a sodium dodecyl sulfa te-polyacrylamide gel; however, the isoform was clearly detected on a two-d imensional gel. We further localized beta-arrestin-1 immunoreactivity in th e sensory neurons of the 5th lumbar dorsal root ganglia. beta-arrestin-1-im munoreactive neurons accounted for approximate to 60% of the sensory neuron s, and approximate to 88% of the beta-Arrestin-1 immunoreactive neurons fel l into a category of small neurons having a diameter of 10-30 mu m. Members of the arrestin superfamily play crucial roles in the desensitizati on of G protein-coupled receptors. Our data demonstrating the presence of b eta-arrestin-1 in the rat dorsal root ganglion at both messenger RNA and pr otein levels support the idea that beta-arrestin-1 participates in receptor desensitization in the sensory neurons. Furthermore, because small-size ne urons of dorsal root ganglion are often implicated in nociception, the pred ominant presence of beta-arrestin-1 immunoreactivity in small-size sensory neurons suggests that beta-arrestin-1 may have a role modulating nociceptiv e signals. (C) 1999 IBRO. Published by Elsevier Science Ltd.