However, the diameter of ACA in SRA images suggested that the vasospasm resulting from prechiasmatic cistern injection was more pronounced. It may be due to blood volumes in basal subarachnoid. At day 7 after SAH, vasospasm on the ACA in cisterna magna injection model was hardly distinguished. In contrast, vasospasm on anterior circulation arteries in prechiasmatic cistern injection model was still identifiable. It implied that the model made by prechiasmatic cistern injection could produce more pronounced and lasting vasospasm of anterior circulation arteries. In summary, SRA provides a practical and precise tool, which can directly evaluate cerebral vasospasm in small animal experimental subarachnoid hemorrhage models. The vasospasm courses of these two injection models are similar; however, model produced by prechiasmatic cistern injection is more suitable for study of anterior circulation vasospasm. In addition to transcription factors chromatin structure plays an important role in the regulation of gene expression. The basic unit of chromatin is nucleosome that is formed by histone octamer containing two copies of H3, H4, H2A and H2B wrapped around by 147 base pairs of DNA. Chromatin structure change includes Ganoderenic-acid-D histone modifications and DNA methylation, histone variant deposition and chromatin remodeling. Histone modifications, especially H3K4 trimethylation and H3K27 trimethylation, have been largely reported to be tightly associated with gene transcription activity. H3K4me3 is associated with highly expressed and/or housekeeping genes whereas H3K27me3 marks under-expressed and/or repressed tissue-specific genes. Both modification marks could be recognized by different chromatin factors through specific protein domains. Ethylene is a plant hormone participating in different processes including germination, flower and leaf senescence, fruit ripening, leaf abscission, root nodulation, programmed cell death, and response to stress and pathogen attack. Genetic and molecular analyses have revealed a response pathway from perception to a series of MAP kinase and finally transduced to two hierarchies of transcription regulation. Genome-wide analysis in plants indicates that H3K4me3 is associated with actively transcribed genes. But how it affects gene expression remains unclear. Some researchers have proposed that this modification may be recognized and bound by specific proteins which act as effectors to control transcription. But other studies have suggested that H3K4me3 could serve as a memory or Ganoderic-acid-D a mark of active genes. In this study we tried to find out the role of H3K4me3 during activation of ethylene-inducible genes. Our results indicated that elevated H3K4me3 was not necessary for the ethylene-induced gene activation but may serve as a mark of transcription activity of the genes. First, H3K4me3 was not detected over AtERF14 and TDR1 before induction and was not increased after ACC treatment. The observations that H3K27me3 did not change over AtERF14, ChiB and TDR1 during ACC induction are consistent with recent results showing that although H3K27me3 on the floral time repressor FLC is inversely correlated with transcriptional activity, the abundance of this mark is not diminished in the first 12h following activation of transcription. Analysis of coldinducible genes has detected H3K27me3 to decline only one to several days after application of the inductive signals. These observations suggest that transcription activation may not involve immediate demethylation of H3K27me3, or the presence of H3K27me3 is not sufficient to impair transcriptional activation during induction. While extensive research has explored the role of miRNAs in processes like development and pathogenesis, the function of miRNAs in the adult nervous system is only just beginning to emerge.