[Changes of CGRP levels in plasma and CGRP mRNA in dorsal root ganglia during endotoxicosis in the rat].

To investigate the changes of both CGRP release and synthesis during endotoxicosis, CGRP mRNA in thoracolumbar dorsal root ganglia (DRG) was determined by the semi-quantity RT-PCR and the CGRP levels in plasma were measured by RIA. The results showed that plasma CGRP, but not mRNA, began to increase 30 min after endotoxin (5 mg/kg, i.v.) administration. On the other hand, the CGRP levels in plasma and CGRP mRNA in DRG were significantly increased by 142% and 32% respectively at the 3 h of injection and by 216% and 85% respectively at the 8 h of injection. The data suggest that not only the release of CGRP from the peripheral organs, but also the transcription of CGRP mRNA and synthesis of CGRP in sensory neurons are increased during the development of endotoxicosis in the rat. Presumably the DRG is an important source of CGRP release in the response to endotoxicosis.