| Abstract: | Abstract— The uniformity and speed of inactivation of mouse brain adenylate cyclase, guanylate cyclase and cyclic nucleotide phosphodiesterase were measured after 6 kW microwave irradiation (MWR). Inactivation of enzymes was uniform throughout the brain during heating and 100% loss of activity was evident after 300 ms. MWR. For comparison of effects of inactivation times on levels of cyclic nucleotides measured in regional brain areas, cyclic AMP and cyclic GMP were estimated after 1.5 kW MWR requiring 4 s of heating and 6 kW MWR requiring 300 ms. Except for corpus striatum, uniformly lower levels of cyclic AMP were measured following 300 ms vs. 4s MWR . There was no change in cyclic GMP levels in regional brain areas after 4s vs. 300 ms MWR . Cyclic AMP and cyclic GMP were measured from the same regional brain tissue samples after 300 ms and ratios calculated. The finding of much lower cyclic AMP:cyclic GMP ratios than had previously been reported suggests that slow inactivation times provide for the measurement of regional brain cyclic nucleotide values which are not consistent with the in-vivo state. |
