Presence of opioid receptor-like (ORL1) receptor mRNA splice variants in peripheral sensory and sympathetic neuronal ganglia

The expression of ORL1 receptor mRNA splice variants is determined in perip heral sensory and sympathetic ganglia and compared to mRNA expression for t he three classic opioid receptor subtypes (mu, delta, and kappa) using the method of reverse transcription-polymerase chain reaction. ORL1, mu, delta and kappa receptor subtype mRNAs are present in human dorsal root ganglia ( DRG) and trigeminal ganglia and rat DRG. ORL1, mu and delta receptor subtyp e mRNAs are present in rat superior cervical ganglia and only ORL1 and delt a receptor mRNAs are present in rat lumbar sympathetic ganglia. Both the OR L1 mRNA splice variants are present in sensory and sympathetic ganglia, how ever, expression of the shorter ORL1 receptor mRNA dominates over expressio n of the longer splice variant in rat brain and DRG, whereas, expression of the longer splice variant is dominant in sympathetic ganglia.