To illuminate the regulating effect of all trans retinoic acid （ATRA ） on gap junctional intercellular communication （GJIC） and connexin 43 （Cx43） ge ne expression in glioma cells

which is tissue and organ specific. Method. Rat C6 glioma cells were exposed to ATRA at a concentration of 1

10

10 0 μmol/L respectively

and the GJIC function of the cells was examined with scr ape loading dye transfer assay 24 hours

48 hours and 72 hours after ATRA treat ment. The effect of ATRA on Cx43 gene expression was measured with semiquantitat ive reverse transcription polymerase chain reaction （RT PCR） 24 hours after ATR A exposure. Results. The GJIC function of C6 glioma cells was significantly increased by ATR A at each concentration applied. The dye passed 4 to 5 rows of cells from the sc raping edge in ATRA treated cells

but only 1 or 2 rows in the control. The augm ent effect was observed 24 hours after each concentration ATRA treatment

and la sted till 72 hours after treatment with 1μmol/L and 10μmol/L ATRA. Forty eigh t hours after exposed to 100μmol/L ATRA

the enhancement of GJIC was less obvi ous. There was no significant increase induced by ATRA on the transcription of C x43 gene

as demonstrated by semiquantitative RT PCR. Conclusion. ATRA turned out to be a potent enhancer on GJIC function in C6 gliom a cells

and the enhancement effect was most probable at post transcriptional l evel.