LEVELS OF CYCLIC NUCLEOTIDES IN MOUSE REGIONAL BRAIN FOLLOWING 300 ms MICROWAVE INACTIVATION¹

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.

Anticonvulsant Drug Actions on In Vitro and In Vivo Levels of Cyclic AMP in the Mouse Brain

“…For the in vivo studies, animals were sacrificed using a 7 kW microwave apparatus described previously by Jones and Stavinoha (1977). This unit utilizes a YJ 1191A magnetron (Amperex Corp., New York, N.Y.) operating at a frequency of 2450 MHz and delivers approximately 5500 W directly to the mouse head.…”

“…Orientation of the animal at the point of maximal electric field strength provided for a power density in the mouse brain of 300-500 W/cm. These heating parameters permitted inactivation of adenylate cyclase, guanylate cyclase, and cyclic nucleotide phosphodiesterase within 300 msec (Jones and Stavinoha, 1977. ) This time corresponded to a brain temperature of 80-85°C and was verified in each animal by use of a 24 gauge needle, copper-cowtantan thermocouple.…”

Cyclic AMP in Female Mouse Brain is Altered by the Adrenocorticotropic Hormone(4–9) Analogue Organon 2766

“…Animals were accepted for dissection only if the recorded brain temperature was between 78 and 95°C. Achieving these brain temperatures with an exposure of 500 ms or less of MWR has been demonstrated to be the most accurate method of killing when determining in vivo regional brain cyclic AMP content (Jones and Stavinoha, 1977;Stavinoha et al, 1978). Each treatment protocol consisted of naive, placebo-injected, and peptide-treated animals; all animals were killed within 10 min of the specified times.…”

Assessment of post‐mortem‐induced changes to the mouse brain proteome

“…1978), cyclic nucleotides (Schmidt et al. 1972b,c; Jones and Stavinoha 1977) and neurotransmitters including serotonin (Joyce 1962), catecholamines and acetylcholine (Guidotti et al. 1974; Ceder and Schuberth 1977).…”