PREPROVASOPRESSIN MESSENGER-RNA IS NOT PRESENT IN DORSAL-ROOT GANGLIAOF THE RAT

Immunohistochemical studies on colchicine-treated rats have suggested that more than half of the neurons in dorsal root ganglia (DRG) contai n vasopressin. Thus, vasopressin would he the most commonly found pept ide in DRG neurons. In the present study we have reexamined the presen ce of vasopressin in DRG neurons, using a sensitive in situ hybridizat ion method employing long riboprobes that will detect very small amoun ts of mRNA. The C3, C6, T2, T12, L2 and L5 DRG were studied. None of t hese ganglia contained any preprovasopressin mRNA. Yet, dense labeling for preprovasopressin mRNA was seen on simultaneously processed hypot halamic sections and a heavy preprotachykinin mRNA expression was seen in adjacent DRG sections. These findings demonstrate that vasopressin is not produced in DRG in normal rats.