Brain research
-
We have previously shown that acute intravenous (i.v.) administration of cocaine increases Fos immunoreactivity in rats under isoflurane anesthesia. Given that Fos expression is a marker of neural activation, the results suggested that isoflurane is appropriate for imaging cocaine effects under anesthesia. However, most imaging research in this area utilizes subjects with a history of repeated cocaine exposure and this drug history may interact with anesthetic use differently from acute cocaine exposure. ⋯ We found that challenge injections of cocaine following a regimen of repeated cocaine exposure resulted in Fos expression in the prefrontal cortex and striatum roughly equivalent to that found in rats who had received the cocaine challenge after a history of vehicle injections. Additionally, isoflurane anesthesia resulted in a heterogeneous attenuation of cocaine-induced Fos expression, with the most robust effect in the orbital cortex but no effect in the nucleus accumbens core (NAcC). These results indicate that cocaine-induced Fos is preserved in the NAcC under isoflurane, suggesting that isoflurane can be used in imaging studies involving cocaine effects in this region.