Fig. 7. Tissue distributions of the putative trout VPAC₁ and VPAC₂ receptors as revealed by RT-PCR. PCR was performed using the sequence-specific primers deduced from the partial cDNA clones for each receptor. Using the sequence-specific primers for trout VPAC₁ receptors, an expected 313-bp product was observed in all tissues with the exception of blood. Prominent products were observed in the liver and intestine. Using sequence-specific primers for trout VPAC₂ receptors, an expected 363-bp product was observed in brain, spleen, heart, liver and intestine. No products were observed in posterior cardinal vein (PCV), kidney, gill and blood. As an internal control, RT-PCR for trout ß-actin was performed. In all tissues, PCR products specific for trout ß-actin were consistently observed. PX, DNA molecular size ladder.