Fig. 5.

Neuronal nicotinic receptor subunit mRNAs encoding α2, α3, α4, α5, α7, β2, β3, and β4 are expressed by cultures of intracardiac parasympathetic neurons. A, Second-round PCR products. Lane 1, 100 bp standards;lanes 2–5 are the PCR products obtained by using the α2/3/4, β2/4, α5/β3, and α7 primers, respectively. In this experiment, α5 and β3 products were amplified in the same reaction (lane 4). Lanes 6 and7 are blank. Lane 8 is the negative control. B, Restriction digestion of PCR products.Lanes 1, 7, 100 bp standards; lanes 2–6contain the digested fragments for the α2/3/4, β2/4, α5, β3, and α7 products, respectively. Note that the α5 and β3 products, although amplified in the same reaction, are digested separately because of different buffer requirements. Fragments identifying each subunit are labeled to the left of each lane. For enzymes used and exact fragment sizes, see Table 1. For clarity in presentation, we have removed the undigested sample routinely run next to each digested product.