Figure 1. RT-PCR analysis of nAChR subunit mRNA levels expressed in the rat VTA.

RT-PCR products in the VTA (A) or in the whole brain (B) from postnatal 14–21-day-old Wistar rats and corresponding to the indicated nAChR subunits or to the housekeeping gene GAPDH were resolved on an agarose gel calibrated by the flanking 100 bp ladders (heavy band is 500 bp) and visualized using ethidium staining. Note that the representative gel shown for whole brain did not contain a sample for the nAChR α3 subunit RT-PCR product, which typically is similar in intensity to the sample on the gel for the VTA. C, results of RT-PCR amplification followed by Southern hybridization with ³²P-labelled, nested oligonucleotides were quantitatively compared after normalization to the GAPDH internal control and to levels of each specific mRNA in whole rat brain (ordinate: +s.e.m.) for the indicated. Note that it is not possible to compare the level of expression of one subunit as message to another's based on the approach used.