DIURNAL-VARIATIONS OF INTERLEUKIN-1-BETA MESSENGER-RNA AND BETA-ACTINMESSENGER-RNA IN RAT-BRAIN

Interleukin-1 beta (IL-1 beta) is posited to play an important physiol ogical role in brain functions in addition to its better defined role in pathology. The experiments described herein were performed to deter mine if IL-1 beta mRNA and beta-actin display diurnal rhythms in vario us areas of brain. Rats were sacrificed at 4 h intervals across a 12:1 2 h light/dark cycle. Hypothalamic, hippocampal and cortical IL-1 beta mRNA peaked just after lights were turned on, declined slightly durin g the remaining light period and stayed low in the dark. There were no significant changes in IL-1 beta mRNA in brain stem or cerebellum sam ples. beta-actin mRNA levels were relatively constant across the day i n the hypothalamus, brain stem and cerebellum. However, beta-actin mRN A levels were lower during the day than during the night in the hippoc ampus and cortex.