Figure 3. Arginine vasopressin receptors in the retina detected by whole-retina reverse transcriptase–polymerase chain reaction. A: Arginine vasopressin (AVP) receptors were detected from a whole wild-type rat retina by reverse transcriptase (RT)–PCR with the indicated primer pairs (Table 1). V1a and V1b receptors were detected. A V2/ARHGAP4 band was also detected, but by cloning and sequencing the RT–PCR product, we concluded that the V2/ARHGAP4 was from the ARHGAP4 gene, which overlaps the V2 receptor gene and is expressed from the opposite DNA strand of the V2 receptor gene. B: No AVP receptor was detected by RT–PCR in dissociated AVP-eGFP-positive cells, as shown in Figure 2B.