Electro-acupuncture markedly increases proenkephalin mRNA in rat striatum and pituitary

Electro-acupuncture (EA) has been found to increase enkephalin content in striatum, hypothalamus and cerebrospinal fluid. Further studies on rat striatum showed that the increase is accompanied by an elevation of enkephalin precursor and processed intermediate levels. In order to characterize the nature of these changes, we have measured the proenkephalin mRNA (PE-mRNA) level in rat striatum and pituitary by recombinant DNA technique. The PE-mRNA was hybridized with human proenkephalin cDNA using a dot-blot procedure. Rats receiving EA showed a 3-5-fold increase of PE-mRNA in striatum beginning at 1 h after the cessation of 30-min EA treatment and lasting 48 h at least. A 3-fold increase of PE-mRNA in pituitary was found immediately after the cessation of EA and a 5-6-fold increase at 1 or 24 h after the termination of EA.