Figure 5. Digitized, color-coded images of CRF1 (Panel A) and CRF2 (Panel B) receptor mRNA expression and receptor autoradiography in adjacent horizontal sections of rat brain. The highest levels of mRNA expression are coded in red; the lowest concentrations are coded in blue. Similarly, the highest densities of receptors labeled with either [125I]oCRF (CRF1 only; panel C) or [125I]sauvagine (CRF1 and CRF2; panel D) are coded in red. There was a good correspondence between the message for a particular receptor subtype and its protein localization and the pharmacological selectivity was retained for the two radioligands (compare C and D).