Radioactive images captured on phosphor screens were visualized using a Cyclone Storage Phosphor Scanner (Packard Bioscience), and the data were analyzed using the OptiQuant program was associated with the scanner. Nonspecific binding was subtracted from total binding and the resultant values represented specific [3H]DAMGO binding in fmol/mg as determined using [3H]microscales. Data are reported as mean values±SEM of data from six animals, with two or three sections in each brain. Statistical significance of the data was determined by independent two-tailed Student’s t-test using Prism 3.0.
